chattr and noatime
rjs3 at andrew.cmu.edu
Fri Jul 18 17:02:07 EDT 2003
On Fri, 18 Jul 2003, joe ritter wrote:
> In most documents on Cyrus performance tuning they
> mention using Chattr +S for /var/spool/imap or other
> such noatime file system options. However I remember
> reading something to the extent that after a certain
> threshold of users there is a law of diminishing
> returnds that sets in with regards to any real
> performance boost. Can somebody comment on this or if
> anybody has some hard numbers regarding this?
chattr +S definately isn't for a performance increase, its to allow
guarantees about the stability of the mail store. It almost certainly
will slow down performance.
Setting noatime should help, because it prevents having to update the
access time metadata whenever a file is read.
I'm not sure why either of these would be affected by diminishing returns
unless the system is already overloaded for other reasons.
Rob Siemborski * Andrew Systems Group * Cyert Hall 207 * 412-268-7456
Research Systems Programmer * /usr/contributed Gatekeeper
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