Re: RAID stripe size question - Mailing list pgsql-performance

From Mark Kirkwood
Subject Re: RAID stripe size question
Date
Msg-id 44BC29C5.5090607@paradise.net.nz
Whole thread Raw
In response to Re: RAID stripe size question  ("Mikael Carneholm" <Mikael.Carneholm@WirelessCar.com>)
List pgsql-performance
Mikael Carneholm wrote:
>
> Btw, here's the bonnie++ results from two different array sets (10+18,
> 4+24) on the MSA1500:
>
>
> LUN: DATA, 24 disks, stripe size 64K
> -------------------------------------
> Version  1.03       ------Sequential Output------ --Sequential Input-
> --Random-
>                     -Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
> --Seeks--
> Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
> /sec %CP
> sesell01        32G 59443  97 118515  39 25023   5 30926  49 60835   6
> 531.8   1
>                     ------Sequential Create------ --------Random
> Create--------
>                     -Create-- --Read--- -Delete-- -Create-- --Read---
> -Delete--
>               files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
> /sec %CP
>                  16  2499  90 +++++ +++ +++++ +++  2817  99 +++++ +++
> 10971 100
>


It might be interesting to see if 128K or 256K stripe size gives better
sequential throughput, while still leaving the random performance ok.
Having said that, the seeks/s figure of 531 not that great - for
instance I've seen a 12 disk (15K SCSI) system report about 1400 seeks/s
in this test.

Sorry if you mentioned this already - but what OS and filesystem are you
using? (if Linux and ext3, it might be worth experimenting with xfs or jfs).

Cheers

Mark

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