Re: Recomendations on raid controllers raid 1+0

[Leigh Dyer <leigh@xxxxxxxxxxxxxx>]

Glyn Astill wrote:
> 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.

Could you build three RAID-1 mirrors on the device, and then stripe that 
using software RAID-0?

Thanks
Leigh

> 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.smet@xxxxxxxxx>
> > To: Glyn Astill <glynastill@xxxxxxxxxxx>
> > Cc: pgsql-performance@xxxxxxxxxxxxxx
> > Sent: Thursday, 13 March, 2008 3:58:41 PM
> > Subject: Re:  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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