Re: advice on raid controller - Mailing list pgsql-performance

From Vivek Khera
Subject Re: advice on raid controller
Date
Msg-id x765jaqaso.fsf@yertle.int.kciLink.com
Whole thread Raw
In response to advice on raid controller  (Richard Jones <rj@last.fm>)
List pgsql-performance
>>>>> "RJ" == Richard Jones <rj@last.fm> writes:

RJ> Hi, i'm on the verge of buying a "MegaRAID SCSI 320-2" raid controller.
RJ> I need it to build a db server using 4x ultra320 scsi disks
RJ> i'm thinking raid 1+0 but will try with raid5 too and compare

No specific tips on that particular RAID, but in general it seems that
you want to *disable* the read-ahead and enable the write-back cache.
This is from reading on the linux megaraid developers list.

Also, for 4 disks, go with RAID 1+0 for your best performance.  I
found it faster.  However, with my 14 disk system, RAID5 is fastest.

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Vivek Khera, Ph.D.                Khera Communications, Inc.
Internet: khera@kciLink.com       Rockville, MD       +1-240-453-8497
AIM: vivekkhera Y!: vivek_khera   http://www.khera.org/~vivek/

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