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My post last week [Solid State Disk on DS8000 Disk Systems] kicked up some dust in the comment section.Fellow blogger BarryB (a member of the elite [Anti-Social Media gang from EMC]) tried to imply that 200GB solid state disk (SSD) drives were different or better than the 146GB drives used in IBM System Storage DS8000 disk systems. I pointed out that they are the actual same physical drive, just formatted differently.
To explain the difference, I will first have to go back to regular spinning Hard Disk Drives (HDD). There are variances in manufacturing, so how do you make sure that a spinning disk has AT LEAST the amount of space you are selling it as? The solution is to include extra. This is the same way that rice, flour, and a variety of other commodities are sold. Legally, if it says you are buying a pound or kilo of flour, then it must be AT LEAST that much to be legal labeling. Including some extra is a safe way to comply with the law. In the case of disk capacity, having some spare capacity and the means to use it follows the same general concept.
(Disk capacity is measured in multiples of 1000, in this case a Gigabyte (GB) = 1,000,000,000 bytes, not to be confused with [Gibibyte (GiB)] = 1,073,741,824 bytes, based on multiples of 1024.)
Let's say a manufacturer plans to sell 146GB HDD. We know that in some cases there might be bad sectors on the disk that won't accept written data on day 1, and there are other marginally-bad sectors that might fail to accept written data a few years later, after wear and tear. A manufacturer might design a 156GB drive with 10GB of spare capacity and format this with a defective-sector table that redirects reads/writes of known bad sectors to good ones. When a bad sector is discovered, it is added to the table, and a new sector is assigned out of the spare capacity.Over time, the amount of space that a drive can store diminishes year after year, and once it drops below its rated capacity, it fails to meet its legal requirements. Based on averages of manufacturing runs and material variances, these could then be sold as 146GB drives, with a life expectancy of 3-5 years.
With Solid State Disk, the technology requires a lot of tricks and techniques to stay above the rated capacity. For example, you can format a 256GB drive as a conservative 146GB usable, with an additional 110GB (75 percent) spare capacity to handle all of the wear-leveling. You could lose up to 22GB of cells per year, and still have the rated capacity for the full five-year life expectancy.
Alternatively, you could take a more aggressive format, say 200GB usable, with only 56GB (28 percent) of spare capacity. If you lost 22GB of cells per year, then sometime during the third year, hopefully under warranty, your vendor could replace the drive with a fresh new one, and it should last the rest of the five year time frame. The failed drive, having 190GB or so usable capacity, could then be re-issued legally as a refurbished 146GB drive to someone else.
The wear and tear on SSD happens mostly during erase-write cycles, so for read-intensive workloads, such as boot disks for operating system images, the aggressive 200GB format might be fine, and might last the full five years.For traditional business applications (70 percent read, 30 percent write) or more write-intensive workloads, IBM feels the more conservative 146GB format is a safer bet.
This should be of no surprise to anyone. When it comes to the safety, security and integrity of our client's data, IBM has always emphasized the conservative approach.[Read More]
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Looks like fellow blogger and arch nemesis BarryB from EMC is once again stirring up trouble, this time he focuses his attention on IBM's leadership in Solid State Disk (SSD) on the IBM System Storage DS8000 disk systems in his post [IBM's amazing splash dance, part deux], a follow-up to [IBM's amazing splash dance] and multi-vendor tirade [don't miss the amazing vendor flash dance].
(Note: IBM [Guidelines] prevent me from picking blogfights, so this post is only to set the record straight on some misunderstandings, point to some positive press about IBM's leadership in this area, and for me to provide a different point of view.)
First, let's set the record straight on a few things. The [RedPaper is still in draft form] under review, and so some information has not yet been updated to reflect the current situation.
I find it amusing that BarryB's basic argument is that IBM's initial release of SSD disk on DS8000 is less than what the potential architecture could be extended to support much more. Actually, if you look at EMC's November release of Atmos, as well as their most recent announcement of V-Max, they basically say the same thing "Stay Tuned, this is just our initial release, with various restrictions and limitations, but more will follow." Architecturally, IBM DS8000 could support a mix of SSD and non-SSD on the same DA pairs, could support RAID6 and RAID10 as well, and could support larger capacity drives or use higher-capacity read-intensive formats. These could all be done via RPQ if needed, or in a follow-on release.
BarryB's second argument is that IBM is somehow "throwing cold water" on SSD technology. That somehow IBM is trying to discourage people from using SSD by offering disk systems with this technology. IBM offered SSD storage on BladeCenter servers LONG BEFORE any EMC disk system offering, and IBM continues to innovate in ways that allow the best business value of this new technology. Take for example this 24-page IBM Technical Brief:[IBM System z® and System Storage DS8000:Accelerating the SAP® Deposits Management Workload With Solid State Drives]. It is full of example configurations that show that SSD on IBM DS8000 can help in practical business applications. IBM takes a solution view, and worked with DB2, DFSMS, z/OS, High Performance FICON (zHPF), and down the stack to optimize performance to provide real business value innovation. Thanks to this synergy,IBM can provide 90 percent of the performance improvement with only 10 percent of the SSD disk capacity as EMC offerings. Now that's innovative!
The price and performance differences between FC and SATA (what EMC was mostly used to) is only 30-50 percent. But the price and performance differences between SSD and HDD is more than an order of magnitude in some cases 10-30x, similar to the differences between HDD and tape. Of course, if you want hybrid solutions that take best advantage of SSD+HDD, it makes more sense to go to IBM, the leading storage vendor that has been doing HDD+Tape hybrid solutions for the past 30 years. IBM understands this better, and has more experience dealing with these orders of magnitude than EMC.
But don't just take my word for it. Here is an excerpt from Jim Handy, from [Objective Analysis] market research firm, in a recent Weekly Review from [Pund-IT] (Volume 5, Issue 23--May 6, 2009):
As for why STEC put out a press release on their own this week without a corresponding IBM press release, I can only say that IBM already announced all of this support back in February, and I blogged about it in my post [Dynamic Infrastructure - Disk Announcements 1Q09]. This is not the first time one of IBM's suppliers has tried to drum up business in this manner. Intel often funds promotions for IBM System x servers (the leading Intel-based servers in the industry) to help drive more business for their Xeon processor.
So, BarryB, perhaps its time for you to take out your green pen and work up another one of your all-too-common retraction and corrections.[Read More]
It's Tuesday, which means IBM announcements, and today IBM made some major announcementsthat support a [Dynamic Infrastructure]! I hinted at this yesterday, choosing the week's theme to be all about Cloud Computing and Alternative Sourcing. I will briefly highlight today's announcements related to storage here, and try to go into more detail over the next few weeks.
This is just a small subset of all the announcements. For more information, see this 28-pagepresentation [Manage the Explosion of Information with IBM Information Infrastructure].
technorati tags: IBM, Dynamic Infrastructure, Ethernet, switches, routers, Cloud Computing, Cloud Storage, Brocade, Juniper Networks, Cisco, IronStack, FCoE, FCoCEE, PoE, DS5000, FC, FDE, TSM, FastBack, TotalStorage, Tivoli, Storage, Productivity Center, Novus, SERP, TS7650, TS77650G, ProtecTIER, Information Infrastructure[Read More]
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Earlier this week, EMC announced its Symmetrix V-Max, following two trends in the industry:
I took a cue from President Obama and waited a few days to collect my thoughts and do my homework before responding.Special thanks to fellow blogger ChuckH in giving me a [handy list of reactions] for me to pick and choose from. It appears that EMC marketing machine feels it is acceptable for their own folks to claim that EMC is doing something first, or that others are catching up to EMC, but when other vendors do likewise, then that is just pathetic or incoherent. Here are a few reactions already from fellow bloggers:
This was a major announcement for EMC, addressing many of the problems, flaws and weaknesses of the earlier DMX-3 and DMX-4 deliverables. Here's my read on this:
When IBM announced its acquisition of XIV over a year ago now, customers were knocking down our doors to get one. This caught two particular groups looking like a [deer in headlights]:
Let me contrast this with the situation Microsoft Windows is currently facing.
In their "I'm a PC" campaign, Microsoft is fighting both fronts. Let's examine two commercials:
IBM's DS8000, HDS USP-V and EMC's Symmetrix are the key players in the Ente Alan Cooper wrote a book that would change that mindset, titled[The Inmates Are Running the Asylum: Why High-Tech Products Drive Us Crazy and How to Restore the Sanity]. This book showed why the situation had gotten out ofhand, and to demand better ease-of-use from all vendors. It was required reading for anyone working in or with IBM's "User Centered Design" teams.I highly recommend this book. IBM recognized this trend early. IBM's SVC, N series and now XIV all offer ease-of-use with While IBM's XIV may not have been the first to introduce a modular, scale-out architectureusing commodity parts managed by sophisticated ease-of-use interfaces, its success might have been the kick-in-the-butt EMC needed to follow the rest of the industry in this direction.
Alan Cooper wrote a book that would change that mindset, titled[The Inmates Are Running the Asylum: Why High-Tech Products Drive Us Crazy and How to Restore the Sanity]. This book showed why the situation had gotten out ofhand, and to demand better ease-of-use from all vendors. It was required reading for anyone working in or with IBM's "User Centered Design" teams.I highly recommend this book.
IBM recognized this trend early. IBM's SVC, N series and now XIV all offer ease-of-use with While IBM's XIV may not have been the first to introduce a modular, scale-out architectureusing commodity parts managed by sophisticated ease-of-use interfaces, its success might have been the kick-in-the-butt EMC needed to follow the rest of the industry in this direction.
While IBM's XIV may not have been the first to introduce a modular, scale-out architectureusing commodity parts managed by sophisticated ease-of-use interfaces, its success might have been the kick-in-the-butt EMC needed to follow the rest of the industry in this direction.Read More]
Continuing this week's series on Pulse 2009 video, we have a double header. Bob Dalton discusses our entry-level IBM System Storage [DS3000] and midrange IBM System Storage [DS4000] disk systems, followed by Dan Thompson discussing [IBM Tivoli Storage Manager FastBack] software.
IBM Tivoli Storage Manager FastBack is the result of IBM's [acquisition of FilesX], a company in Israel that developed software to backup servers at remote branch offices running Microsoft Windows operating system.Read More]