Re: Performance problems with 3ware 9500S-4LP and 2.6.25-rc3

[Arnd Hannemann <hannemann@nets.rwth-aachen.de>]

Andre Noll schrieb:
> Hi
> 
> we are experiencing massive performance problems with two of our
> Linux servers that contain 3ware controllers on a Tyan mainboard and
> a couple of 1T disks.
> 
> During the daily cron job that uses rsync to sync a 500G file system
> from another machine to the raid on the 3ware controller the load
> jumps up, and the machine becomes sluggish as hell. For example, an
> ssh login to that machine takes minutes to complete and ldap becomes
> unreliable while the rsync job is running. Even Nagios complains
> about the machine being down while rsync is running.

Could you give some numbers, please?

However there are some known issues:

http://forums.storagereview.net/index.php?showtopic=25923
http://tumbleweed.org.za/2007/02/16/horrific-performance-with-3ware-raid

Symptons are reasonable performance with large block ops, but really bad performance with small block ops.
time (cp -a linux-2.6.24.2 linux-2.6.24.2b; sync)
Gives me with some tuning 50 seconds here with a 9650SE in a 4 disk raid5 setup. (very bad, single disk will do it in <30s!!!)
But reading and writing large files with large block sizes is usually beyond > 100 MB/s

[snipped a lot]

> Andre

Best regards,
Arnd