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,
Sometimes, it's difficult to explain the products I manage to people outside the IT storage industry. How do you explain FCP vs. FICON, Giant Magnetoresistive (GMR) heads, the SMI-S interface, etc. enough to then explain how your job relates to those technologies. At least my friends and family read this blog, so they can somewhat understand some of the things I am working on. When I visit my folks on Sundays, we sometimes discuss items they read in my blog that week.
In addition to a "take your children to work day", we have discussed within IBM a "take your parents to work day", especially for the young new hires who have a hard time explaining what their new job is to the rest of their family.
Seth Godin points to a video ad to fill a job position and the confusion therein with the "recruiter" who just doesn't understand the job involved.
The problem is not just your parents, but any of your co-workers old enough to be parents who haven't bothered to keep up with the latest advancements in Web 2.0 technology. Here are some examples:
- A project leader working with a technology partner asked if me if there was a difference between a "blog" and a "wiki" and which should his team use. This was not a simple yes/no answer, and involved some explanation, conversation and understanding of what he was trying to accomplish.
- For one of my meetings, someone instant-messaged me asking where it was, was it "face-to-face" (F2F) or Conference call (CC). I replied back, "A2A w/CC" (avatar-to-avatar with voice over conference call). When you are meeting other avatars in-world in Second Life, it gets quite distracting having everyone typing away, with their hands and fingers moving furiously, so we use a conference call to complement our 3D interaction.
That's why I was very excited to seeLinden Lab announces voice beta in Second Life. It won't be fully ready until later this year, but adding voice to Second Life will greatly reduce the hurdles we now have trying to coordinate conference calls with in-world activity.
I realize not everyone can keep up with all the new and different technologies, but the social networking aspects of some of these new developments are worth looking into.
technorati tags: IBM, blog, wiki, social networking, technology, avatar, voice, Second Life, GMR, FICON, FCP, SMI-S
In Storage Technology News, Marc Staimer makes hisSeven network storage predictions for 2007
. Let's take a closer look at each one.
- Federal Rules for Civil Procedures (FRCP) will increase adoption of unstructured data classification, email archive systems and CAS.
CAS continues to flounder, but the rest I can agree with. Regulations are being adopted world wide. Japan has its own Sarbanes-Oxley (SOX) style legislation go into effect in 2008.IBM TotalStorage Productivity Center for Data is a great tool to help classify unstructured file systems. IBM CommonStore for email supports both Microsoft Exchange and Lotus Domino, and can be connected to IBM System Storage DR550 for compliance storage.
- Unified storage systems (combined file and block storage target systems) will become increasingly attractive in 2007, because of their ease of use and simplicity.
I agree with this one also. Our sales of IBM N series in 2006 was great, and looking to continue its strong growth in 2007. The IBM N series brings together FCP, iSCSI and NAS protocols into one disk system. With the SnapLock(tm) feature, N series can store both re-writable data, as well as non-erasable, non-rewriteable data, on the same box. Combine the N series gateway on the front-end with SAN Volume Controller on the back-end, and you have an even more powerful combination.
- Distributed ROBO backup to disk will emerge as the fastest growing data protection solution in 2007.
IDC had a similar prediction for 2006. ROBO refers to "Remote Office/Branch Office", and so ROBO backup deals with how to back up data that is out in the various remote locations. Do you back it up locally? or send it to a central location?Fortunately, IBM Tivoli Storage Manager (TSM) supports both ways, and IBM has introduced small disk and tape drives and auto-loaders that can be used in smaller environments like this. I don't know whether "backup to disk" will be the fastest growing, but I certainly agree that a variety of ROBO-related issues will be of interest this year.
- 2007 will be remembered as the year iSCSI SAN took off because of the much reduced pricing for 10 Gbit iSCSI and the continued deployment of 10 Gbit iSCSI targets.
While I agree that iSCSI is important, I can't say 2007 will be remembered for anything.We have terrible memory in these things. Ask someone what year did Personal Computers (PC) take off, and they will tell you about Apple's famous 1984 commercial. Ask someone when the Internet took off, cell phones took off, etc, and I suspect most will provide widely different answers, but most likely based on their own experience.
For the longest time, I resisted getting a cell phone. I had a roll of quarters in my car, and when I needed to make a call, I stopped at the nearby pay-phone, and made the call. In 1998, pay phones disappeared. You can't find them anymore. That was the year of the cell phones took off, at least for me.
Back to iSCSI, now that you can intermix iSCSI and SAN on the same infrastructure, either through intelligent multi-protocol switches available from your local IBM rep, or through an N series gateway, you can bring iSCSI technology in slowly and gradually. Low-cost copper wiring for 10 Gbps Ethernet makes all this very practical.
Another up-and-coming technology is AoE, or ATA-over-Ethernet. Same idea as iSCSI, but taken down to the ATA level.
- CDP will emerge as an important feature on comprehensive data protection products instead of a separate managed product.
Here, CDP stands for Continuous Data Protection. While normal backups work like a point-and-shoot camera, taking a picture of the data once every midnight for example. CDP can record all the little changes like a video camera, with the option to rewind or fast-forward to a specific point in the day. IBM Tivoli CDP for Files, for example, is an excellent complement to IBM Tivoli Storage Manager.
The technology is not really new, as it has been implemented as "logs" or "journals" on databases like DB2 and Oracle, as well as business applications like SAP R/3.
The prediction here, however, relates to packaging. Will vendors "package" CDP into existing backup products, possibly as a separately priced feature, or will they leave it as a separate product that perhaps, like in IBM's case, already is well integrated.
- The VTL market growth will continue at a much reduced rate as backup products provide equivalent features directly to disk. Deduplication will extend the VTL market temporarily in 2007.
VTL here refers to Virtual Tape Library, such as IBM TS7700 or TS7510 Virtualization Engine. IBM introduced the first one in 1997, the IBM 3494 Virtual Tape Server, and we have remained number one in marketshare for virtual tape ever since. I find it amusing that people are now just looking at VTL technology to help with their Disk-to-Disk-to-Tape (D2D2T) efforts, when IBM Tivoli Storage Manager has already had the capability to backup to disk, then move to tape, since 1993.
As for deduplication, if you need the end-target box to deduplicate your backups, then perhaps you should investigatewhy you are doing this in the first place? People take full-volume backups, and keep to many copies of it, when a more sophisticated backup software like Tivoli Storage Manager can implement backup policies to avoid this with a progressive backup scheme. Or maybe you need to investigate why you store multiple copies of the same data on disk, perhaps NAS or a clustered file system like IBM General Parallel File System (GPFS) could provide you a single copy accessible to many servers instead.
The reason you don't see deduplication on the mainframe, is that DFSMS for z/OS already allows multiple servers to share a single instance of data, and has been doing so since the early 1980s. I often joke with clients at the Tucson Executive Briefing Center that you can run a business with a million data sets on the mainframe, but that there wereprobably a million files on just the laptops in the room, but few would attempt to run their business that way.
- Optical storage that looks, feels and acts like NAS and puts archive data online, will make dramatic inroads in 2007.
Marc says he's going out on a limb here, and that's good to make at least one risky prediction. IBM used to have anoptical library emulate disk, called the IBM 3995. Lack of interest and advancement in technology encouraged IBM to withdraw it. A small backlash ensued, so IBM now offers the IBM 3996 for the System p and System i clients that really, really want optical.
As for optical making data available "online", it takes about 20 seconds to load an optical cartridge, so I would consider this more "nearline" than online. Tape is still in the 40-60 second range to load and position to data, so optical is still at an advantage.
Optical eliminates the "hassles of tape"? Tape data is good for 20 years, and optical for 100 years, but nobody keeps drives around that long anyways. In general, our clients change drives every 6-8 years, and migrate the data from old to new. This is only a hassle if you didn't plan for this inevitable movement. IBM Tivoli Storage Manager, IBM System Storage Archive Manager, and the IBM System Storage DR550 all make this migration very simple and easy, and can do it with either optical or tape.
The Blue-ray vs. DVD debate will continue through 2007 in the consumer world. I don't see this being a major player in more conservative data centers where a big investment in the wrong choice could be costly, even if the price-per-TB is temporarily in-line with current tape technologies. IBM and others are investing a lot of Research and Development funding to continue the downward price curve for tape, and I'm not sure that optical can keep up that pace.
Well, that's my take. It is a sunny day here in China, and have more meetings to attend.
technorati tags: IBM, FRCP, SOX, TotalStorage, Productivity Center, Microsoft, Exchange, Lotus, Domino, DR550, SnapLock, unified storage, NAS, iSCSI, FCP, ROBO, Tivoli, Storage Manager, TSM, Ethernet, AoE, CDP, DB2, Oracle, SAP, VTL, TS7700, TS7510, GPFS, DFSMS, Optical, 3995, 3996, Blue-Ray, D2D2T,DVD
Tonight I had dinner with Henry Daboub (an SVC expert from Houston, TX) and some clients, who asked what I would blog about tonight, and I figured it made sense to blog about the SVC.
Hu Yoshida clarifies his position about storage virtualization, including the statement: "As a result they can not provide the availability, scalability, and performance of a DS8300. If they could, there would be no need for a DS8300."
Of course, if humans descended from apes, why are there still apes? Now that we have cars, why are there still trains? But perhaps a better question is: now that there are supercomputers, why are there still mainframe servers?
The issue is the difference between scale-up versus scale-out. Scale-up is making a single box as big and beefy as possible. When the SVC was introduced, the major vendors all had scale-up designs: IBM ESS 800, HDS Lightning, EMC Symmetrix. Like the mainframe, they were for customers that wanted everything in a single monolithic container.
SAN Volume Controller was the result of IBM Research asking the question, if you could put anyone's software (feature and functionality) on anyone's hardware (monolithic scale-up design), what combination would you choose? What if the brains inside today's monolithic systems could be snapped into the another vendor's frame? What if you could run SRDF on an HDS box, or ShadowImage on an IBM box? The surprising response was that most customers would want a single software for consistency, but wanted the option to choose from different vendors hardware, to negotiate the best price of the commodity iron. Based on this feedback, the SVC was born.
The idea was simple, put all the brains in a separate appliance. The appliance would do the non-disruptive migrations, the caching, the striping, and all the copy services. This lets the customer chose then the hardware they want, any mix of FC and ATA disk, from any vendor.
The SVC design was based on IBM's long history in supercomputers. Using the same "scale-out" technology, the power comes not from having it all in one monolithic box, but rather in a design that combines small nodes together. While the cache is not globally shared, the data is shared between node-pairs, and the logical-to-physical mapping is routed around to all nodes in a cluster. Each SVC node talks to each other SVC node through the FCP ports, eliminating the need for additional wiring. For the most part, each node does its own separate work, but when it needs to, they can communicate across, just like nodes in a supercomputer.
Both the SVC and the DS8300 Turbo have better than 99.999 percent availability, based on redundant components designed for no single point of failure (SPOF). IBM has sold thousands of each, and they have been in the field enough time that we can make that claim. There is nothing between scale-up versus scale-out that makes on inherently more available than the other.
Both the SVC and the DS8300 Turbo can scale from as little as a few TB of disk, to hundreds of TB of disk. We have yet to meet a customer that is too big for the SVC. The DS8300 Turbo is able to scale by adding up to four extension frames, but is still considered a single box from a scale-up perspective. From a processor perspective, an 8-node SVC cluster has 16 Intel Xeon processors, and the DS8300 has 8 POWER5+ processors (dual 4-way). The key advantage of scale-out is that you can add capacity to the SVC in smaller increments. Jumping from a DS8100 (dual 2-way) to a DS8300 (dual 4-way) is a big jump.
SVC remains the fastest disk system in the industry, based on both the SPC-1 and SPC-2 benchmarks. The latest model now supports 8GB per node, for a total of 64GB for an 8-node cluster. This can be used for both read and write non-volatile storage. By comparison, DS8300 Turbo has 32GB write non-volatile storage, and up to 256 GB of read-only cache. The SVC is able to do 155,519 IOPS, faster than the 123,030 IOPS for the DS8300, and of course faster than anything from EMC, HDS, HP or Texas Memory Systems. Of course, workloads vary, and there might be some workloads where the 256GB of read-only cache of the monolithic DS8300 is the better choice.
- copy services
Both SVC and DS8300 Turbo offer FlashCopy (point-in-time copy), Metro Mirror (synchronous) and Global Mirror (asynchronous). SVC provides the additional benefit that it can perform a FlashCopy from one frame to another, and the ability to migrate data seemlessly from one box to another.
Interestingly, IBM has seen a resurgence in both mainframe sales, as well as interest in supercomputers. Both have their place, based on the workload characteristics, and so IBM will continue to offer both modular scale-out designs, as well as monolithic scale-up designs, to meet the different needs of the marketplace.
technorati tags: IBM, disk, SAN, Volume, Controller, DS8300, Turbo, Hu Yoshida, FlashCopy, Metro Mirror, Global Mirror, SPC, benchmarks, HDS, HP, EMC, mainframe, supercomputer
Wrapping up my week in China, I read an article by Li Xing in the local "China Daily" about energy efficiency in buildings. She argues that it is not enough for a building to be energy-efficient on its own, but you have to consider the impact of the other buildings around. Does it reflect the sun so harshly into neighboring windows that people are forced to put up blinds and use artificial light? Does it block the sun, so that rooms that previously could be used with natural sunlight must now be artificially lit?
A similar effect happens with power and cooling in the data center. Servers and storage systems generate heat, and that heat affects all the other equipment in the data center. IBM has the most power-efficient and heat-efficient servers and storage, but that is not enough. You have to consider the heat generated by all systems that might raise overall temperature.
This is what motivated IBM to deliver the IBM Rear Door Heat eXchanger, a member of IBM's CoolBlue(tm) portfolio.
According to a press release:
Research has indicated that water can remove far more heat per volume unit than air. For example, in order to disperse 1,000 watts, with 10 degree temperature difference, only 24 gallons of water per hour is needed, while the same space would require nearly 11,475 cubic feet of air. IBM's Rear Door Heat eXchanger helps keep growing datacenters at safe temperatures, without adding AC units. The unobtrusive solution brings more cooling capacity to areas where heat is the greatest -- around racks of servers with more powerful and multiple processors.
The CoolBlue portfolio of IBM innovations includes comprehensive hardware and systems-management tools for computing environments, enabling clients to better optimize the power consumption, management and cooling of infrastructure at the system, rack and datacenter levels. The CoolBlue portfolio includes IBM PowerConfigurator, PowerExecutive, and Rear Door Heat eXchanger.
The eXchanger works on standard 42U racks, and can help clients deal with the rapid growth of rack-mounted servers and storage on their raised floor. How cool is that!
technorati tags: IBM, Rear Door Heat eXchanger, CoolBlue, power, cooling, efficiency, server, storage