Re: Testing Sandforce SSD

От: Michael Stone
Тема: Re: Testing Sandforce SSD
Дата: ,
Msg-id: 54cd1c80-9b1f-11df-9b6a-001cc0cda50c@msgid.mathom.us
(см: обсуждение, исходный текст)
Ответ на: Re: Testing Sandforce SSD  (Yeb Havinga)
Список: pgsql-performance

Скрыть дерево обсуждения

Testing Sandforce SSD  (Yeb Havinga, )
 Re: Testing Sandforce SSD  (David Boreham, )
  Re: Testing Sandforce SSD  (, )
 Re: Testing Sandforce SSD  (Ben Chobot, )
 Re: Testing Sandforce SSD  (Greg Smith, )
  Re: Testing Sandforce SSD  (Yeb Havinga, )
   Re: Testing Sandforce SSD  (Yeb Havinga, )
    Re: Testing Sandforce SSD  (Yeb Havinga, )
     Re: Testing Sandforce SSD  (Greg Smith, )
  Re: Testing Sandforce SSD  (Greg Smith, )
   Re: Testing Sandforce SSD  ("Joshua D. Drake", )
    Re: Testing Sandforce SSD  (Greg Smith, )
   Re: Testing Sandforce SSD  (Yeb Havinga, )
    Re: Testing Sandforce SSD  (Karl Denninger, )
    Re: Testing Sandforce SSD  (Merlin Moncure, )
     Re: Testing Sandforce SSD  (Yeb Havinga, )
      Re: Testing Sandforce SSD  (Josh Berkus, )
       Re: Testing Sandforce SSD  (Greg Smith, )
        Re: Testing Sandforce SSD  (Scott Marlowe, )
         Re: Testing Sandforce SSD  (Yeb Havinga, )
          Re: Testing Sandforce SSD  (Greg Smith, )
          Re: Testing Sandforce SSD  (Hannu Krosing, )
     Re: Testing Sandforce SSD  (Scott Carey, )
      Re: Testing Sandforce SSD  (Brad Nicholson, )
   Re: Testing Sandforce SSD  ("Joshua D. Drake", )
  Re: Testing Sandforce SSD  (Yeb Havinga, )
   Re: Testing Sandforce SSD  (Yeb Havinga, )
    Re: Testing Sandforce SSD  (Matthew Wakeling, )
     Re: Testing Sandforce SSD  (Yeb Havinga, )
      Re: Testing Sandforce SSD  (Greg Smith, )
       Re: Testing Sandforce SSD  (Yeb Havinga, )
        Re: Testing Sandforce SSD  (Yeb Havinga, )
        Re: Testing Sandforce SSD  (Greg Smith, )
         Re: Testing Sandforce SSD  (Greg Spiegelberg, )
          Re: Testing Sandforce SSD  (Andres Freund, )
          Re: Testing Sandforce SSD  (Greg Smith, )
          Re: Testing Sandforce SSD  (Michael Stone, )
           Re: Testing Sandforce SSD  (Yeb Havinga, )
            Re: Testing Sandforce SSD  (Yeb Havinga, )
             Re: Testing Sandforce SSD  (Greg Spiegelberg, )
            Re: Testing Sandforce SSD  (Michael Stone, )
         Re: Testing Sandforce SSD  (Scott Carey, )
     Re: Testing Sandforce SSD  (Greg Smith, )
      Re: Testing Sandforce SSD  (Matthew Wakeling, )
       Re: Testing Sandforce SSD  (Yeb Havinga, )
        Re: Testing Sandforce SSD  (Greg Spiegelberg, )
         Re: Testing Sandforce SSD  (Greg Smith, )
          Re: Testing Sandforce SSD  (Scott Marlowe, )
           Re: Testing Sandforce SSD  (Michael Stone, )
       Re: Testing Sandforce SSD  (Greg Smith, )
        Re: Testing Sandforce SSD  ("Kevin Grittner", )
        Re: Testing Sandforce SSD  (Hannu Krosing, )
   Re: Testing Sandforce SSD  (Yeb Havinga, )
  Re: Testing Sandforce SSD  (Bruce Momjian, )
 Re: Testing Sandforce SSD  (Merlin Moncure, )
 Re: Testing Sandforce SSD  (Yeb Havinga, )
  Re: Testing Sandforce SSD  (Yeb Havinga, )
   Re: Testing Sandforce SSD  (Merlin Moncure, )
    Re: Testing Sandforce SSD  (Scott Carey, )
 Re: Testing Sandforce SSD  (Chris Browne, )
 Re: Testing Sandforce SSD  (Chris Browne, )

On Wed, Jul 28, 2010 at 03:45:23PM +0200, Yeb Havinga wrote:
>Due to the LBA remapping of the SSD, I'm not sure of putting files
>that are sequentially written in a different partition (together with
>e.g. tables) would make a difference: in the end the SSD will have a
>set new blocks in it's buffer and somehow arrange them into sets of
>128KB of 256KB writes for the flash chips. See also
>http://www.anandtech.com/show/2899/2

It's not a question of the hardware side, it's the software. The xlog
needs to by synchronized, and the things the filesystem has to do to
make that happen penalize the non-xlog disk activity. That's why my
preferred config is xlog on ext2, rest on xfs. That allows the
synchronous activity to happen with minimal overhead, while the parts
that benefit from having more data in flight can do that freely.

Mike Stone


В списке pgsql-performance по дате сообщения:

От: Josh Berkus
Дата:
Сообщение: Re: Pooling in Core WAS: Need help in performance tuning.
От: Tom Lane
Дата:
Сообщение: Re: Questions on query planner, join types, and work_mem