Re: FORGOT TO CONFIGURE RAID! DELL POWEREDGE 2950

От: Jim C. Nasby
Тема: Re: FORGOT TO CONFIGURE RAID! DELL POWEREDGE 2950
Дата: ,
Msg-id: 20070716210210.GZ39272@nasby.net
(см: обсуждение, исходный текст)
Ответ на: Re: FORGOT TO CONFIGURE RAID! DELL POWEREDGE 2950  (Hannes Dorbath)
Список: pgsql-performance

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Re: FORGOT TO CONFIGURE RAID! DELL POWEREDGE 2950  (Hannes Dorbath, )
 Re: FORGOT TO CONFIGURE RAID! DELL POWEREDGE 2950  ("Steinar H. Gunderson", )
 Re: FORGOT TO CONFIGURE RAID! DELL POWEREDGE 2950  (Gregory Stark, )
  Re: FORGOT TO CONFIGURE RAID! DELL POWEREDGE 2950  (Hannes Dorbath, )
   Re: FORGOT TO CONFIGURE RAID! DELL POWEREDGE 2950  ("Jim C. Nasby", )

On Sat, Jul 14, 2007 at 12:19:51PM +0200, Hannes Dorbath wrote:
> Gregory Stark wrote:
> >> From the DELL site it seems this `PERC 5/i' on board controller
> >> (assuming that's what you have) doesn't even have a BBU. If you don't
> >> plan to post here in a few weeks again about data corruption, go out and
> >> shop a serious controller.
> >
> > This is a bit of a strange comment. A BBU will improve performance but
> > Postgres doesn't require one to guarantee data integrity.
> >
> > If your drives have write caching disabled (ie write-through) and your
> > controller does write-through caching and you leave fsync=on and
> > full_page_writes=on which is the default then you shouldn't have any data
> > integrity issues.
>
> That was my point, controllers without BBU usually leave drive caches
> turned on, as with drive caches off performance would be unbearable bad.

Wow, are you sure about that? I've never heard it before, but that'd be
pretty disturbing if it's true...
--
Jim Nasby                                      
EnterpriseDB      http://enterprisedb.com      512.569.9461 (cell)

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