thinking sysadmin

• Your Usable Capacity May Vary – Chuck conducts a thought deployment comparing EMC, HP and NetApp usable space for a 120 disk Exchange deployment. And while he glosses over a couple perhaps non-minor issues (RAID-5 vs RAID-DP and whether EMC’s snapshots are adequately performant), he does hit one of NetApp’s weak spots dead on: Usable capacity, particularly on LUNs if you follow the 100% space reservation recommendation. (Being a NetApp admin these days, I can’t really comment on what he writes about HP – it’s been a long time since I’ve touched that StorageWorks stuff – and I can only repeat what I’ve heard others say about EMC.) More Chuck on this here.
• How to License Windows VMs in a Non Microsoft Virtual Environment: Why Windows Server 2008 Datacenter Edition may be the best choice. (Seen at blog.scottlowe.org.)
• Welcome – My friend, NetApp’s Vaughan Stewart: Chad Sakac highlights some flaws in NetApp’s TR-3697 (“Performance Report: Multiprotocol Performance Test of VMware® ESX 3.5 on NetApp Storage Systems”):
  

  What’s the scoop with:

  * 4K/8K IO size only
  * 2Gbps FC
  * You guys have “throughput/IOPs” shown only in relative, not in absolute.
  * 84 144GB drives with 16 VMs driving the IOMeter workloads with * 10GB of data each on them = 1.3% utilization (rounding up!).

Amazon’s much-awaited Elastic Block Store for EC2 is out this morning; I’m excited to give this a try. A couple downers from the announcement: The pricing is somewhat high – $0.10 per allocated GB per month plus $0.10 per 1 million I/O requests – and the reliability isn’t where I’d like it to be. Specifically, Amazon notes:

Volumes that operate with 20 GB or less of modified data since their most recent Amazon EBS snapshot can expect an annual failure rate (AFR) of between 0.1% – 0.5%, where failure refers to a complete loss of the volume. This compares with commodity hard disks that will typically fail with an AFR of around 4%, making EBS volumes 10 times more reliable than typical commodity disk drives.

Because Amazon EBS servers are replicated within a single Availability Zone, mirroring data across multiple Amazon EBS volumes in the same Availability Zone will not significantly improve volume durability.

That last sentence makes it sound like there is a 0.1% – 0.5% chance of catastrophic data loss of many distinct EBS volumes in an availability zone. If that’s the case, that’s scary – off the top of my head, I’d say your run-of-the mill “Enterprise” SAN doesn’t have a one-in-two hundred risk of catastrophic failure per year.

More links, not all of which I’ve had a chance to fully digest yet:

• Feature Guide: Elastic Block Store
• Amazon EBS (Elastic Block Store) – Bring Us Your Data
• Amazon’s Elastic Block Store explained
• Why Amazon’s Elastic Block Store Matters
• Amazon EBS – Tool and Library Support
• Running MySQL on Amazon EC2 with Elastic Block Store

Since Sun and Amazon removed the limit on the number of OpenSolaris 2008.05 instances able to run on EC2, I’ve been curious – and a little bothered – by the fact that the 2008.05 AMI is 32-bit only. Curious because OpenSolaris shouldn’t have any issues running on a 64-bit EC2 instance (there are other 64-bit OpenSolaris AMIs available on EC2, after all), and a little bothered because there have been long-standing reports of trouble running Solaris on 32-bit architectures, which makes me hesitant to invest much effort in a 32-bit OpenSolaris EC2 environment.

Well, perhaps a 64-bit AMI is forthcoming – I think this is still a beta program – and perhaps Sun’s just trying to save us a buck or two, since the cheapest 64-bit EC2 instance is four times as expensive per hour as the cheapest 32-bit instance.

• Less known Solaris Features: CacheFS – Joerg Moellenkamp at c0t0d0s0.org offers another installment of his excellent Less known Solaris Features series. Of note: “In the recent days there was some discussion about the declaration of the End-of-Feature status for CacheFS which will lead to the announcement of the removal of CacheFS. After a few days of discussion the ARC decided in favour of the removal.” While I’ve never personally used CacheFS – and see no use case for it on the horizon – I’m not thrilled to see it slated for removal as it does sound like it serves an important role. Perhaps ADM or SAM-QFS will become more general to support this style of HSM as well in the future.

• Part III: Since NFSv4 is Stateful It Must Be Less Robust, Right? – “This should conclude my series on this topic, but obviously it’s my blog and like any content provider with no self-respect, I am free to make as many sequels as I want in order to milk the topic for all it is worth. I am going to compare the impact on applications when the NFS client it is using recovers from an NFSv3 and NFSv4 server restart.” Good stuff.

• Performance Report: Multiprotocol Performance Test of VMware® ESX 3.5 on NetApp Storage Systems: A complementary whitepaper to VMware’s own work comparing Fibre Channel, iSCSI and NFS as storage protocols for VMware ESX. (Seen at blog.scottlowe.org.)

According to a blog post on blogs.sun.com, the capacity limit for OpenSolaris 2008.05 on EC2 has been removed.

The blog entry makes it sound like you no longer need to register with Sun to use OpenSolaris on EC2, but that doesn’t appear to be the case – I only see the AMI in my private instances, and the details on the image seem to confirm this.
Read the rest of this entry »

So I returned from a little five-day weekend to sunny Lake Chelan and the Columbia River to an RSS reader bursting at the seams with new posts. By far the best post was one later deleted:

• Amazon Elastic Block Store goes live! (Yeah, that link’s dead – like I said, it was later deleted.) The RightScale folks appear to have inadvertently published a draft (on 8/8, the day after I left town) of their blog post designed to coincide with the release of Amazon’s Elastic Block Store for EC2. They later deleted it, but Google Reader kindly cached the post for me. I won’t repeat anything in the post, nor would I bank on anything written there – would you gamble anything important on a retracted post about a not-yet-released product? I will add one comment: Will EBS attract attention of the lawsuit kind from NetApp? (I mean that comment only partially in jest – and you’d probably have to have seen the original post to know what I’m talking about.)

It’s summer, apparently everyone is on vacation, but, quietly:

• NetApp releases Data ONTAP 7.3 GA!!! Note that it’s a GA, not GD release; release notes are on NOW. (Seen at blog.scottlowe.org.)

Update: For ONTAP 7.3.1 and later, this post is now out-of-date.

It’s been a while since I posted about my unhappiness with NetApp’s FAS2020. And while we’ve replaced our 2020 with a 2050, I still get a lot of traffic to those pages, and a few emailed questions from prospective or new 2020 owners asking about the so-called 8TB limit. Here’s a summary of what I know:
Read the rest of this entry »