thinking sysadmin

• Prediction: Citrix will drop the open source Xen hypervisor for Hyper-V. The rest of the open source world drops Xen for KVM. – Lengthy speculation about the future of Xen now that Hyper-V is out. If this turns out to be correct, I think it leaves Sun in a particularly awkward spot, given that the work they’ve done on integrating Xen with Solaris. (Seen at virtualization.info and vinternals.)

Am I the only one that hates VMware’s patch download site and its corresponding applet? (Maybe – I couldn’t find anyone complaining about it looking quickly on VMware’s message boards, which I found most odd.) I’ve never been able to get it to launch under Firefox, only under IE (even on the same machine with the same JVM). And when it does launch, it is slow as molasses.
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• Daemonic Dispatches: Dissecting SimpleDB BoxUsage – Colin Percival takes a critical look at Amazon’s SimpleDB pricing scheme.

For grins, I tried a quick-and-dirty BFU of a SXCE 79 instance running on EC2 to the latest nightly build this morning. I roughly followed Ben Rockwood’s BFU instructions and didn’t do anything to resolve conflicts beyond running acr. On reboot, it looks like the system panicked – I presume the reason is probably somewhere in here. Console dump after the jump for the curious.
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• S3 data corruption: “We’ve isolated this issue to a single load balancer that was brought into service at 10:55pm PDT on Friday, 6/20. It was taken out of service at 11am PDT Sunday, 6/22. While it was in service it handled a small fraction of Amazon S3′s total requests in the US. Intermittently, under load, it was corrupting single bytes in the byte stream. When the requests reached Amazon S3, if the Content-MD5 header was specified, Amazon S3 returned an error indicating the object did not match the MD5 supplied. When no MD5 is specified, we are unable to determine if transmission errors occurred, and Amazon S3 must assume that the object has been correctly transmitted.” (Seen at Daemonic Dispatches.)

• The Register: Sun’s Niagara 3 will have 16-cores and 16 threads per core – “Each socket is chewing through an insane 256 threads.” I do love a good rumor.
• CloudStatus – Just-launched website for monitoring each Amazon Web Services component in more detail than Amazon gives you. Seen at O’Reilly Radar.

• Blocks & Files: Now HP contributes HPC file system to open source – “HP has contributed its Tru64 UNIX Advanced File System (AdvFS) source code to the open source community, meaning Linux.” It’s been a long time since I’ve used AdvFS (the last time I used Tru64 was in 2003 or so), but it seems to me that this would maybe have been a lot more exciting if it had happened in 2000 or so. They do have a site up on SourceForge with source code already available for download, but I have to wonder how much interest this is going to attract with all the other file systems already out there.
• VMware VROOM!: Scaling real-life Web server workloads – “While the performance of each single-VCPU virtual machine is slightly lower than that of a one-CPU native machine (because of virtualization overhead), the cumulative performance of the multiple virtual machines well exceeds the performance of a large SMP native machine (because serialization penalties are reduced).” In other words, if you know that you have a scale out (instead of scale up) application, you can scale out by scaling up your virtualization server.

I finally got around to installing Ubuntu (Hardy) on my Eee PC this weekend. My only regret: That I waited so long to do it.
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• 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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