Re: performance on new linux box

От: Kevin Grittner
Тема: Re: performance on new linux box
Дата: ,
Msg-id: 4C35E4CA020000250003327E@gw.wicourts.gov
(см: обсуждение, исходный текст)
Ответ на: Re: performance on new linux box  (Ryan Wexler)
Ответы: Re: performance on new linux box  (Ryan Wexler)
Список: pgsql-performance

Скрыть дерево обсуждения

performance on new linux box  (Ryan Wexler, )
 Re: performance on new linux box  (Tom Lane, )
 Re: performance on new linux box  (Rob Wultsch, )
 Re: performance on new linux box  (Andy Colson, )
  Re: performance on new linux box  (Eliot Gable, )
   Re: performance on new linux box  ("Kevin Grittner", )
    Re: performance on new linux box  (Eliot Gable, )
     Re: performance on new linux box  ("Kevin Grittner", )
      Re: performance on new linux box  (Ryan Wexler, )
       Re: performance on new linux box  ("Joshua D. Drake", )
       Re: performance on new linux boxeradmin(11983)i: STATEMENT: update license set expires= '2010-06-15' where lic  (John Rouillard, )
       Re: performance on new linux box  (Craig James, )
       Re: performance on new linux box  (Russell Smith, )
        Re: performance on new linux box  (Samuel Gendler, )
         Re: performance on new linux box  (Ryan Wexler, )
          Re: performance on new linux box  (Greg Smith, )
          Re: performance on new linux box  (Andy Colson, )
       Re: performance on new linux box  ("Joshua D. Drake", )
 Re: performance on new linux box  ("Pierre C", )
 Fwd: performance on new linux box  (Ryan Wexler, )
  Re: performance on new linux box  (Jochen Erwied, )
   Re: performance on new linux box  (Ryan Wexler, )
    Re: performance on new linux box  ("Kevin Grittner", )
    Re: performance on new linux box  (Jochen Erwied, )
     Re: performance on new linux box  (Ryan Wexler, )
      Re: performance on new linux box  (Ben Chobot, )
      Re: performance on new linux box  ("Kevin Grittner", )
       Re: performance on new linux box  (Ryan Wexler, )
        Re: performance on new linux box  (David Boreham, )
        Re: performance on new linux box  ("Kevin Grittner", )
        Re: performance on new linux box  (Craig James, )
         Re: performance on new linux box  (<>, )
          Re: performance on new linux box  (Craig James, )
           Re: performance on new linux box  (Scott Carey, )
            Re: performance on new linux box  (Ben Chobot, )
             Re: performance on new linux box  (Scott Carey, )
              Re: performance on new linux box  (Ben Chobot, )
               Re: performance on new linux box  (Ryan Wexler, )
                Re: performance on new linux box  (Ben Chobot, )
                 Re: performance on new linux box  (Craig Ringer, )
               Re: performance on new linux box  (Scott Carey, )
                Re: performance on new linux box  (Ben Chobot, )
                Re: performance on new linux box  (Greg Smith, )
              Re: performance on new linux box  (Scott Marlowe, )
               Re: performance on new linux box  (Scott Carey, )
               Re: performance on new linux box  (Craig Ringer, )
            Re: performance on new linux box  (Ryan Wexler, )
          Re: performance on new linux box  (David Boreham, )
   Re: performance on new linux box  (Ryan Wexler, )
    Re: performance on new linux box  (Jochen Erwied, )
 Re: performance on new linux box  (Ben Chobot, )
  Re: performance on new linux box  ("Pierre C", )

Ryan Wexler <> wrote:

> One thing I don't understand is why BBU will result in a huge
> performance gain.  I thought BBU was all about power failures?

Well, it makes it safe for the controller to consider the write
complete as soon as it hits the RAM cache, rather than waiting for
persistence to the disk itself.  It can then schedule the writes in
a manner which is efficient based on the physical medium.

Something like this was probably happening on your non-server
machines, but without BBU it was not actually safe.  Server class
machines tend to be more conservative about not losing your data,
but without a RAID controller with BBU cache, that slows writes down
to the speed of the rotating disks.

-Kevin


В списке pgsql-performance по дате сообщения:

От: "Joshua D. Drake"
Дата:
Сообщение: Re: performance on new linux box
От: Craig Ringer
Дата:
Сообщение: Re: Need help in performance tuning.