System Administration

Tell Your Purchasing People: IPv6, VMware

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In the world of system administration there aren’t too many things that are black & white. Everything is a shade of gray where admins solve their own problems however they need to, bending to the local desires & needs of their users or management. Everybody is right, nobody is wrong. I’ve come to realize that, and it’s no big deal. I am convinced, however, that if your organization does not have “fully implemented IPv6 support” and “full support under VMware virtual infrastructure” as requirements for purchasing any new hardware, software, or services, you’re doing it wrong[1][2]. Let’s assume that anything you’re buying now will last 5+ years. In 5+ years we will be out of IPv4 address space[3]. And it …

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…now with 100% more IPv6

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The web server I run this blog’s virtual host from has been IPv6-enabled for about three years. On Monday night I asked myself why I’d never given the blog an AAAA record. So I did. I just looked at the logs, out of curiosity, to see how many of my readers are IPv6-enabled. It’s painful. Discounting myself, 19 unique visitors out of 1683, 1.13%, came in via IPv6. If you aren’t thinking about IPv6 you should start. Enabling IPv6 really isn’t a big problem, by itself, as most ISPs can handle requests like that now. If you’re anything like me the problems that will vex you are the little ones: death by a thousand paper cuts. It’ll be the fact …

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Microsoft Windows Server 2008 SP2 & IPv6

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It looks like Microsoft Windows Server 2008 SP2 changes the way IPv6 works. Perhaps others can corroborate my experiences, or tell me I’m nuts. I’ve been running SP1 with a fully-configured IPv6 stack for some time. I installed SP2 today and two things happened: 1. It appears that the Teredo tunnel now takes precedence over an actual, working IPv6 stack. I was unable to connect via IPv6 to local resources and “ping” returned insanely long response times (300 ms vs. the 1 ms it should have been). To disable this from the command prompt I issued the command: netsh interface teredo set state disabled This smells like a bug to me, and at the very least it’s annoying if you …

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LMGTFY

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At least once a day I have this conversation, usually with one of the same four people: “Hey Bob, do you know what ‘pam_tally(sshd:setcred): unknown option: no_magic_root’ means?” “Have you tried searching for the answer yourself?” “No. Why?” <uncomfortable pause goes here> As such, I adore the creators of “Let Me Google That For You.” http://lmgtfy.com/ (hat tip to my friend Terry Bradshaw for finding this one).

Windows Losing its Default Printer

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For months now my Windows Vista, and now Windows Server 2008 desktop has been losing its default printer every night. I haven’t been able to figure it out until now: it’s the Remote Desktop Client remapping my printers when I connect from home. There are three fixes for this: 1. You can tell your RDP client to not map printers, in the “Local Resources” options tab. This is easy but you have to remember to do it. 2. On the host side on Windows Server 2008 you can go into Administrative Tools->Terminal Services->Terminal Services Configuration, right click the RDP-TCP connection, pick “Properties,” and disable it under the “Client Settings” tab. 3. On the host side on Windows Vista you can …

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Why I Like Wikis

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Around the places I work (and the non-profits I work with, too) we use Atlassian’s Confluence wiki software. With Atlassian offering $5 licenses for Confluence and Jira through the end of the week I thought it’d be a great time to write about how we use our wiki. We love wikis because: 1. They let us easily add & maintain documentation. Let’s say that someone finds an error in a document I wrote (it happens). With old static documentation, like HTML, someone would need to find me and tell me how to fix it. Then I’d need to actually fix it, and re-publish it. With a wiki the person who finds the problem can click “edit” and fix it themselves …

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Servers Too Cold?

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Dear Readers, Has anybody ever had a server get too cold? I’ve seen them get too warm, but there’s very little data about the cold end of things. Can anybody tell me what happens? I’m mainly talking about servers. We do have some IBM tape drives that don’t like the cold, but that’s understandable. In the cold I’d expect issues with fans, especially the cheap ones with sleeve bearings. What else?

Useful Error Messages

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The Dell Server Update Utility script on Linux is really helpful when it can’t run: The Software Update Utility was unable to collect inventory on this system. [/mnt/suu/./bin/Linux/invcol] which: no lockfile in (/usr/local/sbin:/sbin:/bin:/usr/sbin:/usr/bin) invcol Error: Cannot find utilities on the system to execute Inventory Collector. Make sure the following utilities are in the path: tar gzip tail rm mkdir chmod ls basename wc lockfile stat exiting SUU application … This is exactly how errors should be: informative. Instead of quitting suddenly and quietly it’s nice that it tells you what utilities should be installed and in the path, and the “which” error tells you exactly what isn’t there. Excellent.

Arbitrary Milestones

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Scott Lowe’s post this morning echos something I learned a few weeks ago myself: Windows 2008 Server was released as SP1. And I had the same thought as him: WTF. For this we have to thank all of those organizations that have chosen arbitrary releases as the first time they’ll touch new software. From operating systems to disk array firmware, it seems that a lot of system administrators will only start looking at a new version once it’s had a service pack or patch set released for it. And as a result we now have software vendors gaming the system by releasing first versions as SP1. I’d like to share with you all a little secret: all software has bugs. …

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How File Deletions Work

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Q: I deleted a bunch of files from one of my virtual machines yesterday. Deduplication happened overnight, but the total disk space in use didn’t go down. That doesn’t make any sense. Q: I completely evacuated one of the LUNs on my NetApp array, but the NetApp still says that the LUN is almost completely full, even after deduplication. How can that be? A: To understand what is happening you need to know a little bit about how a file system works. A simple way to explain it is that a file system stores the data in a file as data blocks, and it stores the name of the file (and other data, like access times, etc.) in a directory …

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