Re: Recomendations on raid controllers raid 1+0

[Glyn Astill <glynastill(at)yahoo(dot)co(dot)uk>]

Bonie++ benchmarks below.

I believe the the Perc 5/i Raid 10 mode is actually a span of mirrors, rather than the expected stripe of mirrors we should expect from 1+0, and that this is the reason for the shitty performance.


RAID 5
======
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
way5a        32096M 55354  97 201375  59 109586  23 59934  97 427541  33 767.9   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 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++
way5a,32096M,55354,97,201375,59,109586,23,59934,97,427541,33,767.9,1,16,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++

RAID 10
=======
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
Way5a        32096M 53479  99 131640  33 66718  10 58225  95 339287  25 699.1   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 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++
Way5a,32096M,53479,99,131640,33,66718,10,58225,95,339287,25,699.1,1,16,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++


----- Original Message ----
> From: Guillaume Smet <guillaume(dot)smet(at)gmail(dot)com>
> To: Glyn Astill <glynastill(at)yahoo(dot)co(dot)uk>
> Cc: pgsql-performance(at)postgresql(dot)org
> Sent: Thursday, 13 March, 2008 3:58:41 PM
> Subject: Re: [PERFORM] Recomendations on raid controllers raid 1+0
> 
> Glyn,
> 
> On Thu, Mar 13, 2008 at 1:33 PM, Glyn Astill wrote:
> > I'm looking at switching out the perc5i (lsi megaraid) cards from our
> > Dell 2950s for something else as they're crap at raid 10.
> 
> Do you have numbers? Perc 5/i cards perform quite well for us (we have
> a 8 disks RAID 10 in a 2900 server with the traditional Perc 5/i).
> 
> --
> Guillaume


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