Category Archives: Sysadmin

Debian Jessie: TRIM on LVM on LUKS on SSD

Even though I have been using SSDs for more than 5 years on my main machine, I’ve never bothered to set up TRIM properly. At first, that was because the drive didn’t support it – it was the first Intel … Continue reading

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when `scontrol show daemons` returns nothing…

Slurm uses the scontrol show daemons command to figure out what it should run on the machine it is being invoked on. If you have a config file error, that command will return a blank line. And /etc/init.d/slurm-llnl will exit … Continue reading

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Selectively forcing PDF downloads for Firefox

The built-in PDF.js viewer in Firefox is nice, but it still has quite a few bugs. Most of the rendering issues are caused by it not supporting certain PDF features yet. Sometimes one needs to make a PDF with fancy … Continue reading

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more home server disk

I blogged almost 3 years ago about my home server upgrade. The thing has been running very reliably ever since, but I am running out of disk space again. So, time for another upgrade – disk only though this time. … Continue reading

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Migrate MoinMoinWiki to Redmine

I had a few old MoinMoin installs that were due for an upgrade, and I wanted to migrate them to Redmine. I found a migration script at norwinter.com, which I improved a bit. It will handle wiki pages with full … Continue reading

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grub rescue commands

I wasted some time on Friday trying to get a machine with grub 2 installed to boot. The machine booted into Grub’s rescue mode. Grub 2′s rescue mode is nice, but not exactly intuitive (no ‘help’ or ‘?’ command), and … Continue reading

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disk, disk, disk

I started adding 165 TB of disk to one of our clusters today. This is what that looks like – 55 three TB disks: The packaging was not too great; while all disks were well packaged individually, the big boxes … Continue reading

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idle power draw of modern Opteron CPUs

I’ve been curious for a while about how much power Opteron CPUs draw when idle, so I set aside a bit of time to do some measurements. I used a Supermicro 1U system with redundant power supply. The motherboard model … Continue reading

Posted in Environment, Sysadmin | 3 Comments

compression

Before: -rw-r–r– 1 root root 1.1G 2010-10-31 20:19 10125-127-2010-10.error After: -rw-r–r– 1 root root 11M 2010-10-31 20:19 10125-127-2010-10.error.bz2 Bzip2 reduced the file to 1% of its original size. Not bad!

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64K hours

Some disks last a long time. This is an old IBM IDE drive (IC35L040AVVA07-0). smartctl version 5.38 [i686-pc-linux-gnu] Copyright (C) 2002-8 Bruce Allen Home page is http://smartmontools.sourceforge.net/ === START OF READ SMART DATA SECTION === SMART Self-test log structure revision … Continue reading

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