thinking sysadmin

• Flash Forward – Jay Kidd, CTO of NetApp blogs that “NetApp is in the process of certifying enterprise-grade SSDs that you can use in our existing storage shelves.” No dates or pricing announced yet, of course, but he does make an excellent point about SSDs in storage arrays: “For the next few years, you won’t be using a lot of flash capacity in your systems, not just because of the costs. At 10x or more the IOP rate of hard disks, it only takes a small number of SSDs in disk slots to saturate the performance of the array controller. It’s like trying to fly a model airplane in your living room – you’ll run into a system performance wall long before you hit capacity limits. This is another reason that flash as cache is economically efficient – it puts the necessarily small amount of very fast storage at a point in the architecture where you can best exploit the performance.” Not unlike how Sun suggests using SSDs with ZFS. (Seen at Blocks and Files.)

There’s nothing like a long summer weekend followed by an on-site consultant to keep you from updating your blog. But on the bright side, I didn’t have to link to the notebook SSDs are dead – no they’re not kerfluffle.

• NetApp finds NAS could mean ‘never accessed storage’ – “According to a USENIX presentation, 90% of data on NetApp’s networked storage systems was untouched over a 3-month period, raising the issue of whether it would be better placed on cheaper storage.” I would find some irony in that cheaper storage being tape.
• zfs un-benchmarking – “Our rationale for testing was to finally get some numbers that we can provide to users/customers about real zfs performance. There is a huge amount of (largely uncontested) information (emanating mainly from Sun and its agents) that zfs is a very fast file system. We want to test this, on real, live hardware, and report. Well, we can’t do the latter due to Sun’s licensing, but we did do the former. Paraphrasing Mark Twain: ‘Rumors of zfs’s performance have been greatly exaggerated.’” When Joe Landman blogs about performance, I take what he has to say seriously, but given the stability problems he notes, I wonder if – as he suggests – that driver issues are a factor here, and we’re not seeing a generic ZFS issue. (Seen at InsideHPC.)
• Self-protecting archive for SharePoint – “A new archiving product from BridgeHead Software automatically moves older, infrequently-accessed SharePoint items to cheaper archive media and cuts down the SharePoint backup burden.” HSM for SharePoint, apparently? Sounds interesting.
• Since NFSv4 is Stateful It Must Be Less Robust, Right? – “The short answer is no.” Interesting summary of how locking works under NFSv4; although I haven’t used NFSv4, this sounds like a massive improvement over previous versions – can I get the time that I spent debugging locking problems on Linux NFS servers back now?
• Storage Opens Up – Sun releases new JBODs and upgrades Thumper’s hardware. Given that I heard rumors of the Thumper expansion shelves (J4500) maybe a year ago, I’m surprised it took them so long to come out. And is it just me, or do the J4200 and J4400 look a little like someone else’s boxes rebranded?

• Red Hat adopts KVM: what happens to Xen now? – I work in a VMware ESX shop right now (other than all those Solaris Zones and FreeBSD Jails and OpenVZ VEs, that is) – no Xen or KVM. However, given the serious pain in the butt that timekeeping is in Linux guests on ESX, I’ve been sorely tempted to look at running Xen for some Linux virtuals under CentOS 5, in the hopes that this isn’t a problem there. Guess I’ll hold off on that now. (Yeah, I’ve read all the docs, and Linux time sync generally sorta kinda usually works until it doesn’t – it just shouldn’t be that much of a flail.)
• 10 Gigabit Ethernet and VMware – A Match Made in Heaven – Lengthy and interesting article on 10GbE, VMware, consolidation and datacenter Ethernet – dismissive of Infiniband’s chances of becoming the One True Network Fabric.
• Blocks and Files: Between a server or storage array place – More commentary on Chuck’s commentary on HP’s flash announcement. Quote: “Another aspect of this is that a flash SSD cache for a servers needs to plug in to the server’s bus and the supplier doesn’t have to worry about getting a Fibre Channel interface onto flash SSDs which is needed to plug them into existing Fibre Channel slots in a storage array. STEC has an effective monopoly on this (with EMC having its own mini-monopoly because of its exclusivity deal with STEC which ends in a few months) until Emulex’ SSD-tweaked SATA-to-FC bridge chip becomes available at the end of the year. ” Which is probably why NetApp recently announced this instead of flash drives.

Chuck’s got another, uh, thought-provoking blog post up, More Examples Of Why Server Vendors Just Don’t Get Storage, surely intended to ruffle a few feathers. And he does raise some really good points: Most server vendors need more of an SSD strategy than just making a flash drive an option (it’s how you use it, not that you have it!). And as big a fan as I am of ZFS and Sun’s storage options in general, to win in the “enterprise” (and not just, say, HPC) Sun needs to pull everything together into Solaris (from OpenSolaris) and make it less of a DIY operation.
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• HP servers to get flash memory I/O boost – It looks like SSDs will become a common option on server hardware; the real issue will be how to adapt your operating system/file system/application to use them optimally.
• BlueArc’s Titanic benchmark holed – A storage vendor using a non-real-world configuration to optimize benchmark results? Really? Say it ain’t so!

There’s been a lot of noise from the storage industry about flash recently – in particular, noise from EMC and Sun, both of whom recently announced storage products using flash, EMC in January and Sun earlier this month. Below are my thoughts on what EMC and Sun are doing, as well as what NetApp might do. Since I see a fair amount of visitors from all three companies here, if I’ve got something about your employer wrong, please correct me in the comments.
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• Chuck’s Blog: Vendor Differentiation Through Thought Leadership – (Yeah, that title made me gag, too.) Excerpt: “Sun came out loud and strong recently with characteristic unbridled enthusiasm. But, in classic Sun fashion, they missed the point entirely. It’s not just the flash drives (they’re just components, right?) it’s what you can do with them for customers. Seems that their target use case is ZFS running on a storage-oriented server. Not the most compelling use case, IMHO.” Maybe it’s just cynical old me, but I read that as “Sun has some pretty good technology with their server hardware and ZFS, Lustre and SAM-QFS; they might be able to put something together that could really hurt our margins, not just NetApp’s. Flash drives might help them do it. Uh-oh. Maybe we better hurry up and ship Maui.” The Sun/Intel PDF that Chuck links to is actually pretty interesting, although it would have been good to see some more numbers.