[CentOS] slow i/o with a raid 50 on a 3ware controller

[Valeri Galtsev]

Check if writing cache is enabled in 3ware controller configuration. You
may want to have battery backup of controller RAM for that (otherwise
sudden power loss will lead to loss of cache which will make a disaster on
RAID level). 3ware controllers resist to enable cache in absence of
battery backup or weak battery or similar.

Just a shot in a dark.

Valeri

On Wed, August 6, 2014 1:44 pm, Chuck Campbell wrote:
> I have a raid 50 array on a 3ware controller. The box is running centos
> 6.5 and
> the file system is ext4.
>
> I'm going to try some other filesystems, but could anyone suggest any
> alternative raid setups as well as stripe sizes I should try?
>
> The old server uses the same controller on a centos 5.10 setup, using
> ext3, and
> it performs much faster i/o. The old 3ware setup is raid 5.
>
> -chuck
>
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++++++++++++++++++++++++++++++++++++++++
Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247
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