Re: File Systems Compared

Mark Lewis <mark.lewis@mir3.com>

From: Mark Lewis <mark.lewis@mir3.com>
To: Brian Wipf <brian@clickspace.com>
Cc: pgsql-performance@postgresql.org
Date: 2006-12-06T16:55:14Z
Lists: pgsql-performance
> Anyone run their RAIDs with disk caches enabled, or is this akin to
> having fsync off?

Disk write caches are basically always akin to having fsync off.  The
only time a write-cache is (more or less) safe to enable is when it is
backed by a battery or in some other way made non-volatile.

So a RAID controller with a battery-backed write cache can enable its
own write cache, but can't safely enable the write-caches on the disk
drives it manages.

-- Mark Lewis