Re: moving pg_xlog -- yeah, it's worth it!

From: Alvaro Herrera
Subject: Re: moving pg_xlog -- yeah, it's worth it!
Date: ,
Msg-id: 20100211175752.GB3145@alvh.no-ip.org
(view: Whole thread, Raw)
In response to: Re: moving pg_xlog -- yeah, it's worth it!  ("Kevin Grittner")
Responses: Re: moving pg_xlog -- yeah, it's worth it!  (Aidan Van Dyk)
List: pgsql-performance

Tree view

moving pg_xlog -- yeah, it's worth it!  ("Kevin Grittner", )
 Re: moving pg_xlog -- yeah, it's worth it!  (Jesper Krogh, )
  Re: moving pg_xlog -- yeah, it's worth it!  ("Kevin Grittner", )
   Re: moving pg_xlog -- yeah, it's worth it!  (Amitabh Kant, )
    Re: moving pg_xlog -- yeah, it's worth it!  ("Kevin Grittner", )
   Re: moving pg_xlog -- yeah, it's worth it!  (Bruce Momjian, )
    Re: moving pg_xlog -- yeah, it's worth it!  (Scott Marlowe, )
   Re: moving pg_xlog -- yeah, it's worth it!  ("Kevin Grittner", )
    Re: moving pg_xlog -- yeah, it's worth it!  (Alvaro Herrera, )
     Re: moving pg_xlog -- yeah, it's worth it!  (Aidan Van Dyk, )
      Re: moving pg_xlog -- yeah, it's worth it!  ("Kevin Grittner", )
 Re: moving pg_xlog -- yeah, it's worth it!  ("Kevin Grittner", )
  Re: moving pg_xlog -- yeah, it's worth it!  (Alvaro Herrera, )
   Re: moving pg_xlog -- yeah, it's worth it!  (Alvaro Herrera, )
    Re: moving pg_xlog -- yeah, it's worth it!  ("Kevin Grittner", )
     Re: moving pg_xlog -- yeah, it's worth it!  (Alvaro Herrera, )
  Re: moving pg_xlog -- yeah, it's worth it!  (Greg Smith, )
   Re: moving pg_xlog -- yeah, it's worth it!  ("Kevin Grittner", )
    Re: moving pg_xlog -- yeah, it's worth it!  (Ben Chobot, )

Kevin Grittner wrote:

> Another example of why I shouldn't trust my memory.  Per the
> hardware tech:
>
>
> OS:      /dev/sda   is RAID1  -  2  x  2.5" 15k SAS disk
> pg_xlog: /dev/sdb   is RAID1  -  2  x  2.5" 15k SAS disk
>
> These reside on a ServeRAID-MR10k controller with 256MB BB cache.
>
>
> data:    /dev/sdc   is RAID5  -  30 x 3.5" 15k SAS disk
>
> These reside on the DS3200 disk subsystem with 512MB BB cache per
> controller and redundant drive loops.

Hmm, so maybe the performance benefit is not from it being on a separate
array, but from it being RAID1 instead of RAID5?

--
Alvaro Herrera                                http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support


pgsql-performance by date:

From: Scott Marlowe
Date:
Subject: Re: Dell PERC H700/H800
From: "Joshua D. Drake"
Date:
Subject: Re: Dell PERC H700/H800