I'm following theadvice of Tim Sanders, who reminds us ["Don't let the Wookie always win"
In this case, it is not chess pieces, but FUD being slung around like mud between vendors. EMC blogger Chuck Hollis' post [Products vs. Features] correctly pointsout that IBM has invented most nearly everything useful in IT, and sadly a few things we wish we hadn't.Gene Amdahl, who left IBM to start his own company, is credited for coining the phrase describing IBM'sinnovative sales techniques. Wikipedia has a nice write up on the history of[Fear, Uncertainty and Doubt(FUD)].
Nowadays, when you hear "FUD" most storage administrators immediately think of EMC, who have taken this method to anew level of art-form. Take for example two EMC entries from fellow blogger BarryB, on his Storage Anarchist blog:[Not Dead Yet, andPushing Daisies].The first is a reference to a funny scene from a Monty Python movie, and the second one is referring to a terriblenew television program called "Pushing Daisies". (In this show, the main character can bring a dead personback to life for sixty seconds, just long enough to ask a few questions on behalf of his detective friend. He must touch the person again within 60 seconds, or someone else randomly dies instead. I amnot a fan of this concept, and found it a bit morbid and creepy. But I digress.)
It is true I was on vacation the past two weeks, but this was group travel I booked over six months ago before we had the exact dates lined up for our various announcements, and not a last-minute celebration of my recent new job assignment. I got all my assignments for this announcement turned in before leaving for my trip. I never thought of checking with fellow IBM blogger BarryW to make sure that we don't have overlapping vacation schedules, leaving the "blogosphere" unmanned, so to speak, but it is not a bad idea. Fortunately, our IBM PR team was able to make their rebuttal through other means. You can read the recap on Techworld [Marketing Wars by Proxy].
Several astute readers on my blog, however, requested that I add my two cents. Let's take a look at some of BarryB's comments:
...most DS8300's are to this day most frequently bundled as "free" storage with IBM mainframe and server sales.
We just shipped our 15,000th box, so for this absurd statement to be true, more than half would have to be given away as part of a server-and-storage deal?Actually, about a third of our DS8000 sales are sold with servers in the same bundle, and while we do provide discounts from the official list price, that is not the same as "free". The other two thirds are sold into accounts to be used with the existing servers already deployed. So BarryB, your math doesn't work out. (Perhaps you've been taking Hitachi math lessons???)
It is interesting however, that when we do a 4-year TCO comparison, between a normally-discounted DS8000 versus free EMC DMX4 hardware, IBM still has the lower cost, given that most of the price-gouging from EMC happens after the initial sale, through software features, annual Powerpath renewals and MES upgrades. If you are an EMC customer, and you are planning to add more capacity to your DMX, ask EMC to charge you no more than what you originally paid on a dollar-per-GB basis for the initial capacity. That's only fair, right?
...No thin provisioning, or even a commitment to thin provisioning. Just crickets. (Celerra support since Jan 2006...
EMC DMX does not have thin provisioning available today either, so BarryB brings up Celerra, their NAS box? IBM System Storage N series NAS box also has thin provisioning, so if you want thin provisioning you can buy a NAS box from EMC or IBM. Thin provisioning makes sense using NAS protocols, as there are actual commands to "delete a file" that can then free up the related blocks in a thin-provisioned environment. The only way to do this with block-oriented protocols is to get the OS to notify the storage device that blocks can be freed up. As it turns out, IBM's z/OS has such support, which we developed specifically for our thin-provisioning support in our IBM RAMAC Virtual Array disk systems back in the 1990s.For block-oriented devices on most other operating systems, thin provisioning may not be all that it is cracked up to be.
No SATA drives (only DMX-4 supports native SATA-II drives, since Aug’07)
A few people are confused on this. IBM DS8000 has supported FATA for quite some time now, same slower speeds and higher capacities as SATA, but are technically NOT the same as SATA. FATA are designed to provide better protection against vibrational shock, to improve reliability of the drives. IBM felt that if the data was important enough to put on a high-end system, it should get better-than-SATA treatment. If you really want SATA, try our IBM System Storage N series, DS4000 or DS3000 models.
No RAID 6 (DMX-3 has supported multi-dimensional RAID since Q1’07, DMX-4 since Aug'07, ...
IBM N series supports RAID6, but we called it RAID-DP and that confused some people. Same thing, DP stands for Dual Parity, protecting against a double-disk failure. We also just announced RAID6 on our DS4000 series, by the way.
No 4Gb back-end (USP-V since May '07, DMX-4 since Aug’07)
I found this one odd, since BarryB himself in an earlier post explained why 4Gbps back-end made no difference to DMX4 performance in this post [DMX-4 and Oh So Much More
], which I will put into a different color so you can tell it is from a different post:
You may have noticed that there weren't any specific performance claims attributed to the new 4Gb FC back-end. This wasn't an oversight, it is in fact intentional. The reality is that when it comes to massive-cache storage architectures, there really isn't that much of a difference between 2Gb/s transfer speeds and 4Gb/s. Transmit times are really only a tiny portion of I/O overhead, and just don't make that much difference when a massively-cached system is pre-fetching reads, buffering/delaying writes and reordering I/O requests to minimize seek times. Not that 4Gb/s won't help some applications, but most people just won't see any noticeable difference.
In this case, BarryB is right. The IBM DS8000's 2Gbps back-end is not a performance bottleneck. The DS8000 with a 2Gbps back-end is faster than DMX4 with a 4Gbps back-end for business application workloads. EMC doesn't publish SPC benchmarks to deny this, so you will just have to take our word on this.
Still only 1024 maximum disk drives (DMX-3 & 4 support up to 2400 drives, USP-V supports 1152)
I would be curious to see how many customers have more than 1024 drives on any high-end disk array.As we learned back in [Day 2 Storage Symposium
], the average DS8100 has 17.4 TB, and DS8300 has 41.5 TB capacity. Using 500GB drives,that's only 83 spindles. Even with 73GB drives, that's 568 spindles. Plenty of room for growth, so I am notconvinced that higher theoretical upper architectural limits are worth discussing here.
Still only two HARD LPARs (partitions) ..., and even IBM’s mid-tier products support more than 2 storage partitions (in this same announcement)
IBM's two LPARs are TWICE what EMC DMX offers. I don't even know why anyone from EMC would bring this up? While EMC is enjoying their success with VMware, the lack the experience to carry this over to their storage lines. Until EMC offers MORE THAN TWO of any kind of partitions on their high-end offerings, there just is no credibility here. As for our "storage partitions" on our DS4000 line, that is an unfortunate mis-understanding of the press release. On the DS4000, the term "storage partition" is really "LUN masking", dividing up only which disks can be accessed by which hosts, and not dividing up any processor or cache capacity. So this is not the same as any LPAR concept on any other system. For example, a DS4000 with 64 partitions can be attached to 64 hosts, or 64 host-clusters like a Windows MSCS environment or AIX HACMP.
No native Ethernet replication or iSCSI support (Symmetrix has had since 2002)
Again, I found this one odd. On another EMC post, [Vigorous Debates
],Chad Sakac mentions that only 2% of Symmetrix are sold with IP ports, not sure if this is for Ethernet replication, iSCSI attachment, or both (Again, I will use a different color):
On the Symm business (a huge part of EMC’s business – the IP ports are included on 2% of deals. That’s a fact.
Just because engineer can put a feature or function on a box, doesn't mean there is business sense to do so. I would hate for IBM to invest millions of dollars on native iSCSI support, only to have 2% of our DS8000 boxes sold with that feature. Customers who have DS8000 on FC SANs already deployed can easily add iSCSI support either through their SAN switches, or by fronting the DS8000 with an N series gateway. Most customers looking for native iSCSI are the smaller no-SAN-deployed SMB customers, and for them, we have both the DS3300 and the various N series models to choose from.
Well that's my two cents. The DS8000 series remains a strategic part of the IBM System Storage offering matrix, with continued investment in the development, as well as on-going research that we can leverage throughout the IBM company. I would like to read your thoughts on this, post me a comment below.
technorati tags: Tim Sanders, Wookie, C3-PO, Star Wars, chess, FUD, Amdahl, Monty Python, Pushing Daisies, BarryB, Storage Anarchist, IBM, disk, systems, DS8000, DS8300, DS8100, TCO, EMC, DMX, DMX4, thin provisioning, Celerra, z/OS, RAMAC Virtual Array, RVA, SATA, FATA, RAID-6, RAID6, RAID-DP, 4Gb, 4Gbps, 2Gbps, back-end, LPAR, LUN masking, MSCS, AIX, HACMP, DS4000, DS3000, Chad Sakac, iSCSI, Ethernet, IP
|Last week, I was in Austin, and had dinner at [Rudy's Country Store and BBQ]. They offer their self-proclaimed "Worst BBQ in Austin!" with brisket, sausage and other meats by weight. I got a beer, some potato salad, and creamed corn, all at additional cost, of course. When I went to the cashier to pay, I was offered all the white bread I wanted at no additional charge. Are you kidding me? You are going to charge me for beer, but give me 8 to 12 complimentary slices of white bread (practically half a loaf)? Honestly, I consider bread and beer to be basically the same functional food item, differing only in solid versus liquid form. I chose to have only four slices. The food was awesome!|
I am reminded of that from my latest exchange with EMC.It didn't take long after IBM's announcement yesterday of IBM's continued investment in its strategic product set, IBM System Storage DS8000 series, that competitors responded. In particular, fellow blogger BarryB from EMC has a post [DS8000 Finally Gets Thin Provisioning] that pokes fun at the new Thin Provisioning feature.
Interestingly, the attack is not on the technical implementation, which is straightforward and rock-solid, but rather that the feature is charged at a flat rate of $69,000 US dollars (list price) per disk array. BarryB claims that recently EMC Corporate has decided to reduce the price of their own thin provisioning, called Symmetrix Virtual Provisioning (VP) on select subset of models of their storage portfolio, although I have not found an EMC press release to confirm. In other words, EMC will bury the cost of thin provisioning into the total cost for new sales, and stop
shafting, er.. over-charging their existing Symmetrix customers that are interesting in licensing this feature.
BarryB claims this was a lucky coincidence that his blog post happened just days before IBM's announcement.
(Update: While the timing appears suspicious, I am not accusing Mr. Burke in anywrongdoing of insider information of IBM's plans, nor am I aware of any investigations on this matter from the SEC or any other government agency, and apologize if my previous attempt at humor suggested otherwise. BarryB claimsthat the reduction in price was motivated to counter publicly announced HDS's "Switch In On" program, that it is not a secret thatEMC reduced VP pricing weeks ago, effective beginning 3Q09, just not widely advertised in any formal EMC press releases.Perhaps this new VP pricing was only disclosed to just EMC's existing Symmetrix customers, Business Partners, and employees. Perhaps EMC's decision not to announce this in a Press Release was to avoid upsetting all the EMC CLARiiON customers that continue to pay for Thin Provisioning, or to avoid a long line of existing VP customers asking for refunds. In any case, people are innocent until proven otherwise, and BarryB rightfully deserves the presumption of innocence in this regard. I'm sorry, BarryB, for any trouble my previous comments may have caused you.)Instead, let's explore some events over the past year that have led up to this.
Let's start with what EMC previously charged for this feature. Software features like this often follow a common pricing method, based per TB, so larger configurations pay more, but tiered in a manner that larger configurations pay less per TB, combined with a yearly maintenance cost.
(Updated: EMC has asked me nicely not to post their actual list prices,so I will provide rough estimates instead. According to BarryB, these are no longer the current prices, soI present them as historical figures for comparison purposes only.)
|TBs Licensed ||150||100||25|
|Initial List price||$190,000||$160,000||$60,000|
| || || || |
|Software Maintenance (SWMA) percentage||15%||15%||15%|
|Software Maintenance per year||$30,000||$25,000||$9000|
|Number of years||4 years||4 years||4 years|
| || || || |
|Software License Cost (4 years)||$310,000||$260,000||$96,000|
Holy cow! How did EMC get away charging so much for this? To be fair, these are often deeply discounted, a practice common among the industry. However, it was easy for IBMers to show EMC customers that putting SVC or N series gateways in front of their existing EMC disks was more cost effective. Both SVC and N series, as well as IBM's XIV, provide thin provisioning at no additional charge.
HDS offers their own thin provisioning called Hitachi Dynamic Provisioning.Hitachi also offers an SVC-like capability to virtualize storage behind the USP-V. However, I suspect thatfewer than 10 percent of their install base actually licensed this capability because it cost so much. Under the cost pressure from IBM's thin provisioning capabilities in SVC, XIV and N series, Hitachi launched its ["Switch It On"] marketing campaign to activate virtualization and provide some features at no additional charge, including the first 10TB of Hitachi Dynamic Provisioning.
Last week, Martin Glassborow on his StorageBod blog, argued that EMC and HDS should[Set the Wide Stripes Free]. Here is an excerpt:
HDS and EMC are both extremely guilty in this regard, both Virtual Provisioning and Dynamic Provisioning cost me extra as an end-user to license. But this is the technology upon which all future block-based storage arrays will be built. If you guys want to improve the TCO and show that you are serious about reducing the complexity to manage your arrays, you will license for free. You will encourage the end-user to break free from the shackles of complexity and you will improve the image of Tier-1 storage in the enterprise.
Martin is using the term "free" in two contexts above. In the Linux community, we are careful to clarify "free, as in free speech" or "free, as in free beer". Technically, EMC's virtual provisioning is neither, as one has to purchase the hardware to get the feature, so the term "at no additional charge" is more legally correct.
However, the discussion of "free beer" brings me back to my first paragraph about Rudy's BBQ. Nearly everyone eats bread, with the exception of those with [Celiac Disease] that causesan intolerance for gluten protein in wheat, so burying the cost of white bread in the base cost of the BBQ meat is reasonable. In contrast, not everyone drinks beer, and there are probably several people whowould complain if the cost of beer was included in the cost of the BBQ meat, so charging separately forbeer makes business sense.
The same applies in the storage industry. When all (or most) customers of a product can benefit from a feature, it makes sense to include it at no additional charge. When a significant subset might not want to pay a higher base price because they won't use or benefit from a feature, it makes sense to make it optionally priced.
- For the IBM SVC, XIV and N series, all customers can benefit from thin provisioning, so it is included at no additional charge.
- For the IBM System Storage DS8000, perhaps some 30 to 40 percent of our clients have only System z and/or System i servers attached, and therefore would not benefit from this new thin provisioning. It may seem unfair to raise the price on everybody. The $69,000 flat rate was competitively priced against the prices EMC, HDS and 3PAR were charging for similar capability, and lower than the cost to add a new SVC cluster in front of the DS8000. IBM also charges an annual maintenance, but far lower than what others charged as well.
(Note: These list prices are approximate, and vary slightly based on whether you are on legacy, ESA, Servicesuite or ServiceElect software and subscription (S&S) service plans, and the machine type/model. The tables were too complicated to include here in this post, so these numbers are rounded for comparison purposes only.)
|TBs Licensed ||150||100||25|
|IBM flat rate||$69,000||$69,000||$69,000|
| || || || |
|Software Maintenance per year (approx)||$2,000||$2,000||$2,000|
|Number of years||4 years||4 years||4 years|
| || || || |
|Software License Cost (4 years)||$77,000||$77,000||$77,000|
Pricing is more art than science. Getting the right pricing structure that appears fair to everyone involved can be a complicated process.
technorati tags: IBM, Austin, BBQ, thin provisioning, EMC, Virtual Provisioning, SEC, SVC, XIV, N series, Martin Glassborow, HDS, Hitachi, Dynamic Provisioning, System z, System i, DS8000[Read More]
Last week, I presented IBM's strategic initiative, the IBM Information Infrastructure, which is part of IBM's New Enterprise Data Center vision. This week, I will try to get around to talking about some of theproducts that support those solutions.
There has been a lot of attention on XIV in the past few weeks, so I will start with that. Steve Duplessie, anIT industry analyst from Enterprise Strategy Group (ESG) had a post [Adaptec buys Aristos, Tom Cruise, XIV, and Logical Assumptions] with some interesting observations and some sage advice.Val Bercovici on his NetApp Exposed blog, has a post [Has Storage Swift-Blogging Finally Jumped the Shark?] which blasts EMC for their negativity.
(For those not in the USA, swift-blogging is a reference tofalse accusations and negative remarks made during the U.S. 2004 presidential election by the[Swift Boat Veterans], and ["jumping the shark"] is a reference to [a TV show that ran out of interesting and relevant topics].For movie sequels, the comparable phrase is ["nuke the fridge"] in reference to the most recent Indiana Jones' movie.)
I was going to set the record straight on a variety of misunderstandings, rumors or speculations, but I think most have been taken care of already. IBM blogger BarryW covered the fact that SVC now supports XIV storage systems, in his post[SVC and XIV],and addressed some of the FUD already. Here was my list:
- Now that IBM has an IBM-branded model of XIV, IBM will discontinue (insert another product here)
I had seen speculation that XIV meant the demise of the N series, the DS8000 or IBM's partnership with LSI.However, the launch reminded people that IBM announced a new release of DS8000 features, new models of N series N6000,and the new DS5000 disk, so that squashes those rumors.
- IBM XIV is a (insert tier level here) product
While there seems to be no industry-standard or agreement for what a tier-1, tier-2 or tier-3 disk system is, there seemed to be a lot of argument over what pigeon-hole category to put IBM XIV in. No question many people want tier-1 performance and functionality at tier-2 prices, and perhaps IBM XIV is a good step at giving them this. In some circles, tier-1 means support for System z mainframes. The XIV does not have traditional z/OS CKD volume support, but Linux on System z partitions or guests can attach to XIV via SAN Volume Controller (SVC), or through NFS protocol as part of the Scale-Out File Services (SoFS) implementation.
Whenever any radicalgame-changing technology comes along, competitors with last century's products and architectures want to frame the discussion that it is just yet another storage system. IBM plans to update its Disk Magic and otherplanning/modeling tools to help people determine which workloads would be a good fit with XIV.
- IBM XIV lacks (insert missing feature here) in the current release
I am glad to see that the accusations that XIV had unprotected, unmirrored cache were retracted. XIV mirrors all writes in the cache of two separate modules, with ECC protection. XIV allows concurrent code loadfor bug fixes to the software. XIV offers many of the features that people enjoy in other disksystems, such as thin provisioning, writeable snapshots, remote disk mirroring, and so on.IBM XIV can be part of a bigger solution, either through SVC, SoFS or GMAS that provide thebusiness value customers are looking for.
- IBM XIV uses (insert block mirroring here) and is not as efficient for capacity utilization
It is interesting that this came from a competitor that still recommends RAID-1 or RAID-10 for itsCLARiiON and DMX products.On the IBM XIV, each 1MB chunk is written on two different disks in different modules. When disks wereexpensive, how much usable space for a given set of HDD was worthy of argument. Today, we sell you abig black box, with 79TB usable, for (insert dollar figure here). For those who feel 79TB istoo big to swallow all at once, IBM offers "capacity on demand" pricing, where you can pay initially for as littleas 22TB, but get all the performance, usability, functionality and advanced availability of the full box.
- IBM XIV consumes (insert number of Watts here) of energy
For every disk system, a portion of the energy is consumed by the number of hard disk drives (HDD) andthe remainder to UPS, power conversion, processors and cache memory consumption. Again, the XIV is a bigblack box, and you can compare the 8.4 KW of this high-performance, low-cost storage one-frame system with thewattage consumed by competitive two-frame (sometimes called two-bay) systems, if you are willing to take some trade-offs. To getcomparable performance and hot-spot avoidance, competitors may need to over-provision or use faster, energy-consuming FC drives, and offer additional software to monitor and re-balance workloads across RAID ranks.To get comparable availability, competitors may need to drop from RAID-5 down to either RAID-1 or RAID-6.To get comparable usability, competitors may need more storage infrastructure management software to hide theinherent complexity of their multi-RAID design.
Of course, if energy consumption is a major concern for you, XIV can be part of IBM's many blended disk-and-tapesolutions. When it comes to being green, you can't get any greener storage than tape! Blended disk-and-tapesolutions help get the best of both worlds.
Well, I am glad I could help set the record straight. Let me know what other products people you would like me to focus on next.
technorati tags: IBM, XIV, disk, storage, system, Steve Duplessie, ESG, Val Bercovici, NetApp, BarryW, SVC, DS8000, N6000, DS5000, mainframe, z/OS, CKD, SoFS, NFS, ECC, HDD, RAID, UPS, availability, reliability, performance, usability, blended disk-and-tape, green
IBM once again delivers storage innovation!
(Note: The following paragraphs have been updated to clarify the performance tests involved.)
This time, IBM breaks the 1 million IOPS barrier, achieved by running a test workload consisting of a 70/30 mix of random 4K requests. That is 70 percent reads, 30 percent writes, with 4KB blocks. The throughput achieved was 3.5x times that obtained by running the identical workload on the fastest IBM storage system today (IBM System Storage SAN Volume Controller 4.3),
and an estimated EIGHT* times the performance of EMC DMX. With an average response time under 1 millisecond, this solution would be ideal for online transaction processing (OLTP) such as financial recordings or airline reservations.
(*)Note: EMC has not yet published ANY benchmarks of their EMC DMX box with SSD enterprise flash drives (EFD). However, I believe that the performance bottleneck is in their controller and not the back-end SSD or FC HDD media, so I have givenEMC the benefit of the doubt and estimated that their latest EMC DMX4 is as fast as an[IBMDS8300 Turbo] with Fibre Channel drives. If or when EMC publishes benchmarks, the marketplace can make more accurate comparisons. Your mileage may vary.
IBM used 4 TB of Solid State Disk (SSD) behind its IBM SAN Volume Controller (SVC) technology to achieve this amazing result. Not only does this represent a significantly smaller footprint, but it uses only 55 percent of the power and cooling.
The SSD drives are made by [Fusion IO] and are different than those used by EMC made by STEC.
The SVC addresses the one key problem clients face today with competitive disk systems that support SSD enterprise flash drives: choosing what data to park on those expensive drives? How do you decide which LUNs, which databases, or which files should be permanently resident on SSD? With SVC's industry-leading storage virtualization capability, you are not forced to decide. You can move data into SSD and back out again non-disruptively, as needed to meet performance requirements. This could be handy for quarter-end or year-end processing, for example.
For more on this, see the [IBM Press Release] or thearticles in [Network World] by Jon Brodkin, and [Cnet News] by Brooke Crothers.
Our clients have often told us at IBM that performance is one of their top purchase criteria. IBM once again has shown that it listens to the marketplace!
technorati tags: IBM, SVC, million, IOPS, EMC, DMX, Network World, Cnet, Jon Brodkin, Brooke Crothers, benchmark, leading, performance, SSD, EFD, FC, HDD, disk, systems, media
Continuing my catch-up on past posts, Jon Toigo on his DrunkenData
blog, posted a ["bleg"
] for information aboutdeduplication. The responses come from the "who's who" of the storage industry, so I will provide IBM'sview. (Jon, as always, you have my permission to post this on your blog!)
- Please provide the name of your company and the de-dupe product(s) you sell. Please summarize what you think are the key values and differentiators of your wares.
IBM offers two different forms of deduplication. The first is IBM System Storage N series disk system with Advanced Single Instance Storage (A-SIS), and the second is IBM Diligent ProtecTier software. Larry Freeman from NetApp already explains A-SIS in the [comments on Jon's post], so I will focus on the Diligent offering in this post. The key differentiators for Diligent are:
- Data agnostic. Diligent does not require content-awareness, format-awareness nor identification of backup software used to send the data. No special client or agent software is required on servers sending data to an IBM Diligent deployment.
- Inline processing. Diligent does not require temporarily storing data on back-end disk to post-process later.
- Scalability. Up to 1PB of back-end disk managed with an in-memory dictionary.
- Data Integrity. All data is diff-compared for full 100 percent integrity. No data is accidentally discarded based on assumptions about the rarity of hash collisions.
- InfoPro has said that de-dupe is the number one technology that companies are seeking today — well ahead of even server or storage virtualization. Is there any appeal beyond squeezing more undifferentiated data into the storage junk drawer?
Diligent is focused on backup workloads, which has the best opportunity for deduplication benefits. The two main benefits are:
- Keeping more backup data available online for fast recovery.
- Mirroring the backup data to another remote location for added protection. With inline processing, only the deduplicated data is sent to the back-end disk, and this greatly reduces the amount of data sent over the wire to the remote location.
- Every vendor seems to have its own secret sauce de-dupe algorithm and implementation. One, Diligent Technologies (just acquired by IBM), claims that their’s is best because it collapses two functions — de-dupe then ingest — into one inline function, achieving great throughput in the process. What should be the gating factors in selecting the right de-dupe technology?
As with any storage offering, the three gating factors are typically:
- Will this meet my current business requirements?
- Will this meet my future requirements for the next 3-5 years that I plan to use this solution?
- What is the Total Cost of Ownership (TCO) for the next 3-5 years?
Assuming you already have backup software operational in your existing environment, it is possible to determine thenecessary ingest rate. How many "Terabytes per Hour" (TB/h) must be received, processed and stored from the backup software during the backup window. IBM intends to document its performance test results of specific software/hardwarecombinations to provide guidance to clients' purchase and planning decisions.
For post-process deployments, such as the IBM N series A-SIS feature, the "ingest rate" during the backup only has to receive and store the data, and the rest of the 24-hour period can be spent doing the post-processing to find duplicates. This might be fine now, but as your data grows, you might find your backup window growing, and that leaves less time for post-processing to catch up. IBM Diligent does the processing inline, so is unaffected by an expansion of the backup window.
IBM Diligent can scale up to 1PB of back-end data, and the ingest rate does not suffer as more data is managed.
As for TCO, post-process solutions must have additional back-end storage to temporarily hold the data until the duplicates can be found. With IBM Diligent's inline methodology, only deduplicated data is stored, so less disk space is required for the same workloads.
- Despite the nuances, it seems that all block level de-dupe technology does the same thing: removes bit string patterns and substitutes a stub. Is this technically accurate or does your product do things differently?
IBM Diligent emulates a tape library, so the incoming data appears as files to be written sequentially to tape. A file is a string of bytes. Unlike block-level algorithms that divide files up into fixed chunks, IBM Diligent performs diff-compares of incoming data with existing data, and identifies ranges of bytes that duplicate what already is stored on the back-end disk. The file is then a sequence of "extents" representing either unique data or existing data. The file is represented as a sequence of pointers to these extents. An extent can vary from2KB to 16MB in size.
- De-dupe is changing data. To return data to its original state (pre-de-dupe) seems to require access to the original algorithm plus stubs/pointers to bit patterns that have been removed to deflate data. If I am correct in this assumption, please explain how data recovery is accomplished if there is a disaster. Do I need to backup your wares and store them off site, or do I need another copy of your appliance or software at a recovery center?
For IBM Diligent, all of the data needed to reconstitute the data is stored on back-end disks. Assuming that all of your back-end disks are available after the disaster, either the original or mirrored copy, then you only need the IBM Diligent software to make sense of the bytes written to reconstitute the data. If the data was written by backup software, you would also need compatible backup software to recover the original data.
- De-dupe changes data. Is there any possibility that this will get me into trouble with the regulators or legal eagles when I respond to a subpoena or discovery request? Does de-dupe conflict with the non-repudiation requirements of certain laws?
I am not a lawyer, and certainly there are aspects of[non-repudiation] that may or may not apply to specific cases.
What I can say is that storage is expected to return back a "bit-perfect" copy of the data that was written. Thereare laws against changing the format. For example, an original document was in Microsoft Word format, but is converted and saved instead as an Adobe PDF file. In many conversions, it would be difficult to recreate the bit-perfect copy. Certainly, it would be difficult to recreate the bit-perfect MS Word format from a PDF file. Laws in France and Germany specifically require that the original bit-perfect format be kept.
Based on that, IBM Diligent is able to return a bit-perfect copy of what was written, same as if it were written to regular disk or tape storage, because all data is diff-compared byte-for-byte with existing data.
In contrast, other solutions based on hash codes have collisions that result in presenting a completely different set of data on retrieval. If the data you are trying to store happens to have the same hash code calculation as completely different data already stored on a solution, then it might just discard the new data as "duplicate". The chance for collisions might be rare, but could be enough to put doubt in the minds of a jury. For this reason, IBM N series A-SIS, that does perform hash code calculations, will do a full byte-for-byte comparison of data to ensure that data is indeed a duplicate of an existing block stored.
- Some say that de-dupe obviates the need for encryption. What do you think?
I disagree. I've been to enough [Black Hat] conferences to know that it would be possible to read thedata off the back-end disk, using a variety of forensic tools, and piece together strings of personal information,such as names, social security numbers, or bank account codes.
Currently, IBM provides encryption on real tape (both TS1120 and LTO-4 generation drives), and is working withopen industry standards bodies and disk drive module suppliers to bring similar technology to disk-based storage systems.Until then, clients concerned about encryption should consider OS-based or application-based encryption from thebackup software. IBM Tivoli Storage Manager (TSM), for example, can encrypt the data before sending it to the IBMDiligent offering, but this might reduce the number of duplicates found if different encryption keys are used.
- Some say that de-duped data is inappropriate for tape backup, that data should be re-inflated prior to write to tape. Yet, one vendor is planning to enable an “NDMP-like” tape backup around his de-dupe system at the request of his customers. Is this smart?
Re-constituting the data back to the original format on tape allows the original backup software to interpret the tape data directly to recover individual files. For example, IBM TSM software can write its primary backup copies to an IBM Diligent offering onsite, and have a "copy pool" on physical tape stored at a remote location. The physical tapes can be used for recovery without any IBM Diligent software in the event of a disaster. If the IBM Diligent back-end disk images are lost, corrupted, or destroyed, IBM TSM software can point to the "copy pool" and be fully operational. Individual files or servers could be restored from just a few of these tapes.
An NDMP-like tape backup of a deduplicated back-end disk would require that all the tapes are in-tact, available, and fully restored to new back-end disk before the deduplication software could do anything. If a single cartridge fromthis set was unreadable or misplaced, it might impact the access to many TBs of data, or render the entire systemunusable.
In the case of a 1PB of back-end disk for IBM Diligent, you would be having to recover over a thousand tapes back to disk before you could recover any individual data from your backup software. Even with dozens of tape drives in parallel, could take you several days for the complete process.This represents a longer "Recovery Time Objective" (RTO) than most people are willing to accept.
- Some vendors are claiming de-dupe is “green” — do you see it as such?
Certainly, "deduplicated disk" is greener than "non-deduplicated" disk, but I have argued in past posts, supportedby Analyst reports, that it is not as green as storing the same data on "non-deduplicated" physical tape.
- De-dupe and VTL seem to be joined at the hip in a lot of vendor discussions: Use de-dupe to store a lot of archival data on line in less space for fast retrieval in the event of the accidental loss of files or data sets on primary storage. Are there other applications for de-duplication besides compressing data in a nearline storage repository?
Deduplication can be applied to primary data, as in the case of the IBM System Storage N series A-SIS. As Larrysuggests, MS Exchange and SharePoint could be good use cases that represent the possible savings for squeezing outduplicates. On the mainframe, many master-in/master-out tape applications could also benefit from deduplication.
I do not believe that deduplication products will run efficiently with “update in place” applications, that is high levels of random writes for non-appending updates. OLTP and Database workloads would not benefit from deduplication.
- Just suggested by a reader: What do you see as the advantages/disadvantages of software based deduplication vs. hardware (chip-based) deduplication? Will this be a differentiating feature in the future… especially now that Hifn is pushing their Compression/DeDupe card to OEMs?
In general, new technologies are introduced on software first, and then as implementations mature, get hardware-based to improve performance. The same was true for RAID, compression, encryption, etc. The Hifn card does "hash code" calculations that do not benefit the current IBM Diligent implementation. Currently, IBM Diligent performsLZH compression through software, but certainly IBM could provide hardware-based compression with an integrated hardware/software offering in the future. Since IBM Diligent's inline process is so efficient, the bottleneck in performance is often the speed of the back-end disk. IBM Diligent can get improved "ingest rate" using FC instead of SATA disk.
Sorry, Jon, that it took so long to get back to you on this, but since IBM had just acquired Diligent when you posted, it took me a while to investigate and research all the answers.
technorati tags: IBM, Diligent, Jon Toigo, DrunkenData, bleg, deduplication, A-SIS, NetApp, ProtecTier, inline, post-process, back-end, disk, data integrity, hash, collision, ingest rate, VTL, non-repudiation, extent, bit-perfect, Microsoft Word, Adobe PDF, diff, Black Hat, encryption, compression, Hifn, FC, SATA
Yesterday, I started this week's topic discussing the various areas of exploration to helpunderstand our recent press release of the IBM System Storage SAN Volume Controller and itsimpressive SPC-1 and SPC-2 benchmark results that ranks it the fastest disk system in the industry.
Some have suggested that since the SVC has a unique design, it should be placed in its own category,and not compared to other disk systems. To address this, I would like to define what IBM meansby "disk system" and how it is comparable to other disk systems.
When I say "disk system", I am going to focus specifically on block-oriented direct-access storage systems, which I will define as:
One or more IT components, connected together, that function as a whole, to serve as a target forread and write requests for specific blocks of data.
Clarification: One could argue, and several do in various comments below, that there are other typesof storage systems that contain disks, some that emulate sequential access tape libraries, some that emulate file-systems through CIFS or NFS protocols, and some that support thestorage of archive objects and other fixed content. At the risk of looking like I may be including or excluding such to fit my purposes, I wanted to avoid apples-to-orangescomparisons between very different access methods. I will limit this exploration to block-oriented, direct-access devices. We can explore these other types of storage systems in later posts.
People who have been working a long time in the storage industry might be satisfied by this definition, thinkingof all the disk systems that would be included by this definition, and recognize that other types of storage liketape systems that are appropriately excluded.
Others might be scratching their heads, thinking to themselves "Huh?" So, I will provide some background, history, and additional explanation. Let's break up the definition into different phrases, and handle each separately.
- read and write requests
Let's start with "read and write requests", which we often lump together generically as input/output request, or just I/O request. Typically an I/O request is initiated by a host, over a cable or network, to a target. The target responds with acknowledgment, data, or failure indication. A host can be a server, workstation, personal computer, laptop or other IT device that is capable of initiating such requests, and a target is a device or system designed to receive and respond to such requests.
(An analogy might help. A woman calls the local public library. She picks up the phone, and dials the phone number of the one down the street. A man working at the library hears the phone ring, answers it with "Welcome to the Public Library! How can I help you?" She asks "What is the capital city of Ethiopia?" and replies "Addis Ababa." and hangs up. Satisfied with this response, she hangs up. In this example, the query for information was the I/O request, initiated by the lady, to the public library target)
Today, there are three popular ways I/O requests are made:
- CCW commands over OEMI, ESCON or FICON cables
- SCSI commands over SCSI, Fibre Channel or SAS cables
- SCSI commands over Ethernet cables, wireless or other IP communication methods
- specific blocks of data
In 1956, IBM was the first to deliver a disk system. It was different from tape because it was a "direct access storage device" (the acronym DASD is still used today by some mainframe programmers). Tape was a sequential media, so it could handle commands like "read the next block" or "write the next block", it could not directly read without having to read past other blocks to get to it, nor could it write over an existing block without risking overwriting the contents of blocks past it.
The nature of a "block" of data varies. It is represented by a sequence of bytes of specific length. The length is determined in a variety of ways.
- CCW commands assume a Count-Key-Data (CKD) format for disk, meaning that tracks are fixed in size, but that a track can consist of one or more blocks, and can be fixed or variable in length. Some blocks can span off the end of one track, and over to another track. Typical block sizes in this case are 8000 to 22000 bytes.
- SCSI commands assume a Fixed-Block-Architecture (FBA) format for disk, where all blocks are the same size, almost always a power of two, such as 512 or 4096 bytes. A few operating systems, however, such as i5/OS on IBM System i machines, use a block size that doesn't follow this power-of-two rule.
- one or more IT components
You may find one or more of the following IT components in a disk system:
- customized or general-purpose processing chips
- memory, such as RAM, Flash, or similar
- batteries and/or other power supply
- Host attachment cards or ports
- motorized platter(s) covered in magnetic coating with a read/write head to move over its surface. These are often referred to as Hard Disk Drive (HDD) or Disk Drive Modules (DDM), and are manufacturedby companies like Seagate or Hitachi Global Storage Technologies.
A set of HDD can be accessed individually, affectionately known as JBOD for Just-a-bunch-of-disk, or collectively in a RAID configuration.
Memory can act as the high-speed cache in front of slower storage, or as the storage itself. For example, the solid state disk that IBM announced last week is entirely memory storage, using Flash technology.
Lately, there are two popular packaging methods for disk systems:
- Monolithic -- all the components you need connected together inside a big refrigerator-sized unit, with options to attach additional frames. The IBM System Storage DS8000, EMC Symmetrix DMX-4 and HDS TagmaStore USP-V all fit this category.
- Modular -- components that fit into standard 19-inch racks, often the size of the vegetable drawer inside a refrigerator, that can be connected externally with other components, if necessary, to make a complete disk system. The IBM System Storage DS6000, DS4000, and DS3000 series, as well as our SVC and N series, fall into this category.
Regardless of packaging, the general design is that a "controller" receives a request from its host attachment port, and uses its processors and cache storage to either satisfy the request, or pass the request to the appropriate HDD,and the results are sent back through the host attachment port.
In all of the monolithic systems, as well as some of the modular ones, the controller and HDD storage are contained in the same unit. On other modular systems, the controller is one system, and the HDD storage is in a separate system, and they are cabled together.
- serve as a target
The last part is that a disk system must be able to satisfy some or all requests that come to it.
(Using the same analogy used above, when the lady asked her question, the guy at the public library knew the answer from memory, and replied immediately. However, for other questions, he might need to look up the answer in a book, do a search on the internet, or call another library on her behalf.)
Some disk systems are cache-only controllers. For these, either the I/O request is satisfied as a read-hit or write-hit in cache, or it is not, and has to go to the HDD. The IBM DS4800 and N series gateways are examples of this type of controller.
Other systems may have controller and disk, but support additional disk attachment. In this case, either the I/O request is handled by the cache or internal disk, or it has to go out to external HDD to satisfy the request. IBM DS3000 series, DS4100, DS4700, and our N series appliance models, all fall into this category.
So, the SAN Volume Controller is a disk system comprising of one to four node-pairs. Each node is a piece of IT equipment that have processors and cache. These node-pairs are connected to a pair of UPS power supplies to protect the cache memory holding writes that have not yet been de-staged. The combination of node-pairs and UPS acting as a whole, is able to serve as a target to SCSI commands sent over Fibre Channel cables on a Storage Area Network (SAN). To read some blocks of data, it uses its internal cache storage to satisfy the request, and for others, it goes out to external disk systems that contain the data required. All writes are satisfied immediately in cache on the SVC, and later de-staged to external disk when appropriate.
As of end of 2Q07, having reached our four-year anniversary for this product, IBM has sold over 9000 SVC nodes, which are part of more than 3100 SVC disk systems. These things are flying off the shelves, clocking in a 100% YTY growth over the amount we sold twelve months ago. Congratulations go to the SVC development team for their impressive feat of engineering that is starting to catch the attention of many customers and return astounding results!
So, now that I have explained why the SVC is considered a disk system, tomorrow I'll discuss metrics to measure performance.
technorati tags: IBM, SVC, HDD, DDM, DS4800, SVC, SAN Volume Controller, EMC, HDS, HP, DS4100, DS4700, Flash, RAM, solid-state, disk, system, controller, array, RAID, I/O, IO, request, read, write,
TonyPearson による の変更
"The murals in restaurants are on par with the food in museums."
--- Peter De Vries
The quote above applies to blogs as well. Those about competitive products of which the blogger has little to no hands-on experience tend to be terribly misleading or technically inaccurate. We saw this last month as Sun Microsystems' Jeff Savit tried to discuss the IBM System z10 EC mainframe.
This time, it comes from EMC bloggers discussing NetApp equipment, and by association, IBM System Storage N series gear.I was going to comment on the ridiculous posts by fellow bloggers from EMC about SnapLock compliance feature on the NetApp, but my buddies at NetApp had already done this for me, saving me the trouble.
The hysterical nature of writing from EMC, and the calm responses from NetApp, speak volumes about the culturesof both companies.
The key point is that none of the "Non-erasable, Non-Rewriteable" (NENR) storage out there are certified as compliant by any government agency on the planet. Governments just aren't in the business of certifying such things. The best you can get is a third-party consultant, such as [Cohasset Associates], to help make decisions that are best for each particular situation.
In addition to SnapLock on N series, IBM offers the [IBM System Storage DR550], WORM tape and optical systems, all of which have been deemed compliant to the U.S. Securities and Exchange Commission [SEC 17a-4] federal regulations by Cohasset Associates. For medical patient records and images like X-rays, IBM offers the Grid Medical Archive Solution [GMAS]designed to meet the requirements of the U.S. Health Insurance Portability and Accountability Act[HIPAA].For other government or industry regulations, consult with your legal counsel.
technorati tags: IBM, EMC, NetApp, N series, SnapLock, compliance, compliant, NENR, WORM, DR550, SEC, 17a-4, GMAS, HIPAA, tape, optical, disk, systems, Cohasset Associates, z10, EC, mainframe, Sun
While EMC bloggers garnered media attention last year pointing out the faulty mathematics from HDS, an astute reader pointed me to EMC's own [DMX-4 specification sheet
],updated for its 1TB SATA disk.I've chosen just the minimum and maximum number of drives RAID-6 data points for non-mainframe platforms:
|RAID level||# drives||500GB SATA||1TB SATA|
In the first two rows, the numbers appear as expected. For example, 96 drives would be 12 sets of 6+2 RAID ranks, meaning 72 drives' worth of data, so nearly 36TB for 500GB drives, and nearly 72TB for 1TB drives. With 14+2 RAID-6, thenyou would have 84 drives' worth of data, so 42TB and 84TB respectively match expectations.
Where EMC appears miscalculating is having 20x more drives, as the numbers don't match up. For 1920 drives inRAID-6, you would expect 20x more usable capacity than the 96 drive configurations. For 6+2 configurations, one would expect 720TB and 1440TB respectively. For 14+2 configurations, one wouldexpect 840TB and 1680TB, respectively.
Perhaps EMC DMX-4 can't address more than 600TB for the entire system? Does EMC purposely limit the benefitsof these larger drives? It does question why someone might go from 500GB to 1TB drives, if the maximum configuration only gives about 40TB more capacity.Fellow IBM blogger Barry Whyte questioned the use of SATA in an expensive DMX-4 system, in his post[One Box Fits All - Or Does It], and now perhaps there are good reasons to question 1TB from a capacityperspective as well.
technorati tags: IBM, EMC, DMX-4, 500GB, 1TB, RAID-6, HDS, SATA
I am still wiping the coffee off my computer screen, inadvertently sprayed when I took a sip while reading HDS' uber-blogger Hu Yoshida's post on storage virtualization andvendor lock-in
. This blog appears to be the text version of theirfunny video
While most of the post is accurate and well-stated, two opinions particular caught my eye. I'll be nice and call them opinions, since these are blogs, and always subject to interpretation. I'll put quotes around them so that people will correctly relate these to Hu, and not me.
"Storage virtualization can only be done in a storage controller. Currently Hitachi is the only vendor to provide this."
-- Hu Yoshida
Hu, I enjoy all of your blog entries, but you should know better. HDS is fairly new-comer to the storage virtualization arena, so since IBM has been doing this for decades, I will bring you and the rest of the readers up to speed. I am not starting a blog-fight, just want to provide some additional information for clients to consider when making choices in the marketplace.
First, let's clarify the terminology. I will use 'storage' in the broad sense, including anything that can hold 1's and 0's, including memory, spinning disk media, and plastic tape media. These all have different mechanisms and access methods, based on their physical geometry and characteristics. The concept of 'virtualization' is any technology that makes one set of resources look like another set of resources with more preferable characteristics, and this applies to storage as well as servers and networks. Finally, 'storage controller' is any device with the intelligence to talk to a server and handle its read and write requests.
Second, let's take a look at all the different flavors of storage virtualization that IBM has developed over the past 30 years.
IBM introduces the S/370 with the OS/VS1 operating system. "VS" here refers to virtual storage, and in this case internal server memory was swapped out to physical disk. Using a table mapping, disk was made to look like an extension of main memory.
IBM introduces the IBM 3850 Mass Storage System (MSS). Until this time, programs that ran on mainframes had to be acutely aware of the device types being written, as each device type had different block, track and cylinder sizes, so a program written for one device type would have to be modified to work with a different device type. The MSS was able to take four 3350 disks, and a lot of tapes, and make them look like older 3330 disks, since most programs were still written for the 3330 format. The MSS was a way to deliver new 3350 disk to a 3330-oriented ecosystem, and greatly reduce the cost by handling tape on the back end. The table mapping was one virtual 3330 disk (100 MB) to two physical tapes (50 MB each). Back then, all of the mainframe disk systems had separate controllers. The 3850 used a 3831 controller that talked to the servers.
IBM invents Redundant Array of Independent Disk (RAID) technology. The table mapping is one or more virtual "Logical Units" (or "LUNs") to two or more physical disks. Data is striped, mirrored and paritied across the physical drives, making the LUNs look and feel like disks, but with faster performance and higher reliability than the physical drives they were mapped to. RAID could be implemented in the server as software, on top or embedded into the operating system, in the host bus adapter, or on the controller itself. The vendor that provided the RAID software or HBA did not have to be the same as the vendor that provided the disk, so in a sense, this avoided "vendor lock-in".Today, RAID is almost always done in the external storage controller.
IBM introduces the Personal Computer. One of the features of DOS is the ability to make a "RAM drive". This is technology that runs in the operating system to make internal memory look and feel like an external drive letter. Applications that already knew how to read and write to drive letters could work unmodified with these new RAM drives. This had the advantage that the files would be erased when the system was turned off, so it was perfect for temporary files. Of course, other operating systems today have this feature, UNIX has a /tmp directory in memory, and z/OS uses VIO storage pools.
This is important, as memory would be made to look like disk externally, as "cache", in the 1990s.
IBM AIX v3 introduces Logical Volume Manager (LVM). LVM maps the LUNs from external RAID controllers into virtual disks inside the UNIX server. The mapping can combine the capacity of multiple physical LUNs into a large internal volume. This was all done by software within the server, completely independent of the storage vendor, so again no lock-in.
IBM introduces the Virtual Tape Server (VTS). This was a disk array that emulated a tape library. A mapping of virtual tapes to physical tapes was done to allow full utilization of larger and larger tape cartridges. While many people today mistakenly equate "storage virtualization" with "disk virtualization", in reality it can be implemented on other forms of storage. The disk array was referred to as the "Tape Volume Cache". By using disk, the VTS could mount an empty "scratch" tape instantaneously, since no physical tape had to be mounted for this purpose.
Contradicting its "tape is dead" mantra, EMC later developed its CLARiiON disk library that emulates a virtual tape library (VTL).
IBM introduces the SAN Volume Controller. It involves mapping virtual disks to manage disks that could be from different frames from different vendors. Like other controllers, the SVC has multiple processors and cache memory, with the intelligence to talk to servers, and is similar in functionality to the controller components you might find inside monolithic "controller+disk" configurations like the IBM DS8300, EMC Symmetrix, or HDS TagmaStore USP. SVC can map the virtual disk to physical disk one-for-one in "image mode", as HDS does, or can also map virtual disks across physical managed disks, using a similar mapping table, to provide advantages like performance improvement through striping. You can take any virtual disk out of the SVC system simply by migrating it back to "image mode" and disconnecting the LUN from management. Again, no vendor lock-in.
The HDS USP and NSC can run as regular disk systems without virtualization, or the virtualization can be enabled to allow external disks from other vendors. HDS usually counts all USP and NSC sold, but never mention what percentage these have external disks attached in virtualization mode. Either they don't track this, or too embarrassed to publish the number. (My guess: single digit percentage).
Few people remember that IBM also introduced virtualization in both controller+disk and SAN switch form factors. The controller+disk version was called "SAN Integration Server", but people didn't like the "vendor lock-in" having to buy the internal disk from IBM. They preferred having it all external disk, with plenty of vendor choices. This is perhaps why Hitachi now offers a disk-less version of the NSC 55, in an attempt to be more like IBM's SVC.
IBM also had introduced the IBM SVC for Cisco 9000 blade. Our clients didn't want to upgrade their SAN switch networking gear just to get the benefits of disk virtualization. Perhaps this is the same reason EMC has done so poorly with its "Invista" offering.
So, bottom line, storage virtualization can, and has, been delivered in the operating system software, in the server's host bus adapter, inside SAN switches, and in storage controllers. It can be delivered anywhere in the path between application and physical media. Today, the two major vendors that provide disk virtualization "in the storage controller" are IBM and HDS, and the three major vendors that provide tape virtualization "in the storage controller" are IBM, Sun/STK, and EMC. All of these involve a mapping of logical to physical resources. Hitachi uses a one-for-one mapping, whereas IBM additionally offers more sophisticated mappings as well.
technorati tags: IBM, disk, tape, storage, virtualization, Hu Yoshia, HDS, Hitachi, TagmaStore, USP, NSC, disk-less, SAN Volume Controller, LVM, AIX, RAID, SAN, blade, Sun, STK, Cisco, EMC, Invista,