I have benched different sripe sizes with different file systems, and the perfmance differences can be quite dramatic.

Theoreticaly a smaller stripe is better for OLTP as you can write more small transactions independantly to more different disks more often than not, but a large stripe size is good for Data warehousing as you are often doing very large sequential reads, and a larger stripe size is going to exploit the on-drive cache as you request larger single chunks from the disk at a time.

It also seems that different controllers are partial to different defaults that can affect their performance, so I would suggest that testing this on two different controller cards man be less than optimal.

I would also recommend looking at file system.  For us JFS worked signifcantly faster than resier for large read loads and large write loads, so we chose JFS over ext3 and reiser.

I found that lower stripe sizes impacted performance badly as did overly large stripe sizes.

Alex Turner
NetEconomist

On 16 Sep 2005 04:51:43 -0700, bmmbn <[EMAIL PROTECTED]> wrote:
Hi Everyone

The machine is IBM x345 with ServeRAID 6i 128mb cache and 6 SCSI 15k
disks.

2 disks are in RAID1 and hold the OS, SWAP & pg_xlog
4 disks are in RAID10 and hold the Cluster itself.

the DB will have two major tables 1 with 10 million rows and one with
100 million rows.
All the activities against this tables will be SELECT.

Currently the strip size is 8k. I read in many place this is a poor
setting.

Am i right ?


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