Re: Quad processor options - Mailing list pgsql-performance

From Grega Bremec
Subject Re: Quad processor options
Date
Msg-id 20040512045832.GA10035@elbereth.noviforum.si
Whole thread Raw
In response to Re: Quad processor options  ("scott.marlowe" <scott.marlowe@ihs.com>)
Responses Re: [ADMIN] Quad processor options  ("scott.marlowe" <scott.marlowe@ihs.com>)
List pgsql-performance
...and on Tue, May 11, 2004 at 03:02:24PM -0600, scott.marlowe used the keyboard:
>
> If you get the LSI megaraid, make sure you're running the latest megaraid
> 2 driver, not the older, slower 1.18 series.  If you are running linux,
> look for the dkms packaged version.  dkms, (Dynamic Kernel Module System)
> automagically compiles and installs source rpms for drivers when you
> install them, and configures the machine to use them to boot up.  Most
> drivers seem to be slowly headed that way in the linux universe, and I
> really like the simplicity and power of dkms.
>

Hi,

Given the fact LSI MegaRAID seems to be a popular solution around here, and
many of you folx use Linux as well, I thought sharing this piece of info
might be of use.

Running v2 megaraid driver on a 2.4 kernel is actually not a good idea _at_
_all_, as it will silently corrupt your data in the event of a disk failure.

Sorry to have to say so, but we tested it (on kernels up to 2.4.25, not sure
about 2.4.26 yet) and it comes out it doesn't do hotswap the way it should.

Somehow the replaced disk drives are not _really_ added to the array, which
continues to work in degraded mode for a while and (even worse than that)
then starts to think the replaced disk is in order without actually having
resynced it, thus beginning to issue writes to non-existant areas of it.

The 2.6 megaraid driver indeed seems to be a merged version of the above
driver and the old one, giving both improved performance and correct
functionality in the event of a hotswap taking place.

Hope this helped,
--
    Grega Bremec
    Senior Administrator
    Noviforum Ltd., Software & Media
    http://www.noviforum.si/

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