On 10/7/06, Nico Mittenzwey <[EMAIL PROTECTED]> wrote:
"memtest86" http://www.memtest86.com/
If you are using a large amount of ECC memory, you may find it necessary to keep track of Single Bit Errors and look for "weak" DIMMs using something like the EDAC/bluesmoke drivers (http://bluesmoke.sourceforge.net) and a userspace memory tester. On a 264 node cluster with 8-16GB RAM, I had to weed out weak memory over a period of months. A given node running a memory tester would show no SBEs for a day or more, then suddenly show a huge burst. Another system might have a more consistently incrementing SBE counter. Now, ECC was working, so applications like the memory tester weren't having problems. However, I couldn't reliably reboot this cluster because the BIOS would often refuse to boot unless a node was powered off for say, five minutes. I wrote up more of this experience on the Real World Tech forum: http://www.realworldtech.com/forums/index.cfm?action=detail&id=69894&threadid=69639&roomid=11 It looks like the latest version of Stresslinux has a 2.6.16.18 kernel, so it should have the EDAC drivers included. Plus, it has the userspace memtester. Memtest86 is nice, but it didn't support checking the ECC counters on the the cluster I mention above. It couldn't help me weed out DIMMs at all. See http://agenda.clustermonkey.net/index.php/Memory for some more info about this (links to LWN articles and a list of supported drivers in 2.6.16). I wasn't aware of the EDAC wiki until I saw it linked from the bluesmoke page just now. It will tell you what chipset support is coming. http://buttersideup.com/edacwiki/ I would be interested to hear about other what kind of single bit error rates other people see on their clusters. -- Andrew Shewmaker _______________________________________________ Beowulf mailing list, [email protected] To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
