--On Wednesday, May 15, 2019 12:33 PM +0200 Dieter Kluenter
<[email protected]> wrote:
Would a small logpurge interval strongly influence the system's
performance? If it would, a both ways on-the-fly change based on
automatic watch of the actual size of the accesslog database
might be interesting if the high rate writes are a seldom event.
If it wouldn't, setting a small enough interval from the beggining would
do the trick.
It all depends on the syncrepl intervals. The logpurge interval should
consider the timegap between 2 synchronization operations. It is hard to
say to what extend performance will be influenced, you should find out
yourself and set the system optimum, it might vary between a few ours
and a few days.
It depends on how many changes fit within a time period. I always suggest
a frequent log purge setting, as this significantly reduces the impact on
the system. For example, say that the log purge deletes all entries > 1
day old. If you have 10,000 changes per day that are about evenly
distributed, then we end up with purges like this (depending on purge
interval):
Purge once a day: 10,000 deletes per purge
Purge twice a day: 5,000 deletes per purge
Purge four times a day: 2,500 deletes per purge
etc.
I usually have the log purge interval set to 4 hours (6 times a day). As
I've discussed before, it's better to purge frequently, as server
processing comes to a halt while the purge is ongoing. With a single daily
purge interval in a production environment that has thousands of changes,
I've seen slapd pause for several minutes (I.e., stop processing requests).
Changing the configuration to have a purge interval of every 4 hours made
it so slapd only paused for less than a second and was not noticable to
applications.
--Quanah
--
Quanah Gibson-Mount
Product Architect
Symas Corporation
Packaged, certified, and supported LDAP solutions powered by OpenLDAP:
<http://www.symas.com>
