On 04/07/2013 02:29 PM, Jov wrote:
from the pg doc：
http://www.postgresql.org/docs/devel/static/wal-reliability.html :
On Linux, IDE drives can be queried using hdparm -I; write caching is enabled if there is a * next to Write cache. hdparm -W 0 can be used to turn off write caching. SCSI drives can be queried using sdparm. Use sdparm --get=WCE to check whether the write cache is enabled and sdparm --clear=WCE to disable it.
The previous paragraph does say "Consumer-grade IDE and SATA drives are particularly likely
to have write-back caches that will not survive a power failure."
I guess it's reasonable to replace "IDE" with "ATA/SATA" though it's pretty minor. It'd be nice to confirm that the method for disabling the write cache on fbsd is still correct and applies to SATA drives.
-- Craig Ringer http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services