Re: freebsd/softupdates for data dir
От | Mark Kirkwood |
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Тема | Re: freebsd/softupdates for data dir |
Дата | |
Msg-id | 4431D591.30500@paradise.net.nz обсуждение исходный текст |
Ответ на | freebsd/softupdates for data dir (Miguel <mmiranda@123.com.sv>) |
Ответы |
Re: freebsd/softupdates for data dir
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Список | pgsql-performance |
Miguel wrote: > Hi, reading the archives i cant find a clear answer about softupdates in > freebsd, is it recommended to enable it for the data directory? > There is a pretty good article about softupdates and journelling here: http://www.usenix.org/publications/library/proceedings/usenix2000/general/full_papers/seltzer/seltzer_html/index.html and in the freebsd docs here: http://www.freebsd.org/doc/handbook/configtuning-disk.html Postgres does not do a lot of file meta-data operations (unless you do a *lot* of CREATE/DROP INDEX/TABLE/DATABASE), so the performance gains associated with softupdates will probably be minimal. I've always left them on, and never had any issues...(even after unscheduled power loss - which happened here yesterday). As I understand it, the softupdate code reorders *metadata* operations, and does not alter data operations - so the effect of fysnc(2) on a preexisting file is not changed by softupdates being on or off. Cheers Mark
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