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
