Re: Recomendations on raid controllers raid 1+0

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(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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