On 04/01/2010 09:23 AM, Max Eaves wrote: > Hi there, > > I hope this gets through....my first posting on this dist.list. > > I am running Centos 5.4 with a 2.6.18-164.15.1.el5 kernel (x86_64) > kernel using a rather "homebrew" backblaze system > (http://blog.backblaze.com/) system. > > The mdadm version is: mdadm - v2.6.9 - 10th March 2009 > > It uses a number of Silicon Image 3124 (sIL 3124) cards and a number of > multiplier port cards (sIL3132) to read a large number of disks. > > I have 45 disks arranged into 3 mdadm raid sets of 15 disks. These 15 > disks are raided using RAID6. > > The problem I have is this: > > At random times, the RAID decides that it needs to resynchronise > /dev/md10 /dev/md11 and /dev/md12. There is no error or log event in > /var/log/messages, but the first thing I notice is that the performance > of the RAID array drops, and checking out "cat /proc/mdadm" shows all > three RAID re synchronising themselves. > > ARRAY /dev/md0 level=raid1 num-devices=2 > uuid=7d7b19e6:56cc90cc:3cb166bd:b8086f29 (system boot) (not a problem) > ARRAY /dev/md1 level=raid1 num-devices=2 > uuid=3782d93d:a491ffd4:f32c1014:94a2b3f7 (system LVM) (not a problem) > ARRAY /dev/md10 level=raid6 num-devices=15 > uuid=5ca86e2a-3b86-4c0b-9a7a-59143bdcd0f1 (partition 1) (problem) > ARRAY /dev/md11 level=raid6 num-devices=15 > uuid=61188c90-4825-44c5-8fac-9bc82a5799fe (partition 2) (problem) > ARRAY /dev/md12 level=raid6 num-devices=15 > uuid=fa939816-1d0f-4eaa-98dd-c131449c3921 (partition 3) (problem) > > These re-synchronisation events take about a week to complete (the RAID > is 18TB a pop) > > I know that the performance of this system is not great, but I wonder if > this resynchronisation is occurring because of some I/O time-out. > > Oddly enough, a restart of the server fixes the problem for a couple of > days, and then problem occurs again (humm - not good). > > I'm happy to post logs etc....just let me know what you need. Disable /etc/cron.weekly/99-raid-check. They aren't resyncronizing, they are actually just checking themselves for consistency, but because the 2.6.18 kernel didn't have a different word for it in the output of /proc/mdstat it just looks that way. I can't remember if the version of mdadm in centos 5.4 has the /etc/sysconfig/raid-check config file, but if it does, it's easy to disable the weekly check there. -- Doug Ledford <dledford@xxxxxxxxxx> GPG KeyID: CFBFF194 http://people.redhat.com/dledford Infiniband specific RPMs available at http://people.redhat.com/dledford/Infiniband
Attachment:
signature.asc
Description: OpenPGP digital signature
