CentOS - Aug 2014 - slow i/o with a raid 50 on a 3ware controller

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

-- 
ACCEL Services, Inc.| Specialists in Gravity, Magnetics |  (713)993-0671 ph.
                     |   and Integrated Interpretation   |  (713)993-0608 fax
448 W. 19th St. #325|            Since 1992             |  (713)306-5794 cell
  Houston, TX, 77008 |          Chuck Campbell           | campbell at
accelinc.com
                     |  President & Senior Geoscientist  |

      "Integration means more than having all the maps at the same
scale!"

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
>
> --
> ACCEL Services, Inc.| Specialists in Gravity, Magnetics |  (713)993-0671
> ph.
>                      |   and Integrated Interpretation   |  (713)993-0608
> fax
> 448 W. 19th St. #325|            Since 1992             |  (713)306-5794
> cell
>   Houston, TX, 77008 |          Chuck Campbell           |
> campbell at accelinc.com
>                      |  President & Senior Geoscientist  |
>
>       "Integration means more than having all the maps at the same
scale!"
>
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> http://lists.centos.org/mailman/listinfo/centos
>

++++++++++++++++++++++++++++++++++++++++
Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247
++++++++++++++++++++++++++++++++++++++++

On 6.8.2014 20:44, 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.
Do you have barriers enabled?
Just another shot in the dark, but 5 didn't have that.
If you have battery backed Cache with your Controller, you can safely
disable barriers anyway.

-- 
Kind Regards, Markus Falb

On Wed, Aug 6, 2014 at 2:44 PM, Chuck Campbell <campbell at accelinc.com>
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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