A B wrote:
Hi there! I'm trying to comprehend the current status of filesystem settings and PostgreSQL settings. If I run on a machine (using Linux and ext3) with no battery backed raid controller then I should use fsync=on and disable the write cache on my harddrives to avoid corruption. If I had a controller with battery, then I could use fsync=off, but I should still disable the write cache?
no, you would still want fsync on, otherwise commits are left in main memory. fsync forces the commits to be written to the controller cache which has the battery. most of the raid systems I've used that battery backed cache have storage media with proper cache flushing, and the raid controller issues the appropriate commands to insure the on-drive buffers get flushed too. Its usually when you use cheap desktop SATA that you can get into trouble, as long as you're using proper server grade storage like SAS, FC, SCSI, it generally works right.
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