inconsistent performance

[Simon Jones]

hello chaps,

anyone have an idea why i'm seeing inconsistent performance on all 3
of my gateway servers?  Nothing shows up errors in the maillog and
MailScanner --Lint checks out ok but from time to time the machines
will choke and i'll stack 2k and rising messages up in the hold queue.

one day they'll work fine and the hold queue will be normal, then all
of a sudden they'll start backing up.

I have postfix reading from mysql for the relay_domains /
relay_recipients and transport maps as well as logging to a seperate
db on the same seperate db server for mailwatch.

the mysql db has dual oppy's with 10gb ram so it's pretty beefy and
doesn't seem to be maxed at all.

the gateways run fairly heavy but are by no means topping out.  I've
tried dropping max children and the batch processing settings but to
no avail.

any ideas would be really appreciated.

thanks

SMJ