Hi, On Thu, Feb 07, 2008 at 05:50:20PM +0100, Andreas Kurz wrote: > On Feb 7, 2008 10:08 AM, Lino Moragon <[EMAIL PROTECTED]> wrote: > > Hi list, > > I'm running a HA 2 node active / passive cluster with drbd and mysql. > > I was told about the ocf monitoring function of the yet available mysql > > ocf script. > > The base monitor function in the mysql RA does only a check if there > is a process with the PID of your mysql instance running. > > > Could you tell me the advantages or disadvantages of implementing this > > monitoring function? > > We have a quite similar cluster in our production environment and I > encountered no problems with a "deeper" mysql check. I installed a > small test db (the 'City' db from the mysql site) that's exclusive for > heartbeat's monitor selects so no table locking problems should occur. > Of course you should not run out of available mysql connections and > choose timeout values appropriate to your system load. > > A monitor example: > <op id="op_DB_community-monitor" interval="10s" name="monitor" > timeout="10s" start_delay="30s"> > <instance_attributes id="ia_op_DB_community-monitor"> > <attributes> > <nvpair id="op_DB_community-monitor-check_level" > name="OCF_CHECK_LEVEL" value="10"/> > </attributes> > </instance_attributes> > </op> > > > I mean surely it does have benefits, but what if I my php > > webapplications e.g. generate too much load, too large and complex > > queries and the timeout value exceeds? > > Then the server would restart or failover and then that would repeat > > itself on and on and my ha-cluster wouldn't be a hacluster anymore. > > Have you any experience what possible things could happen to a mysql > > server and what would be the reasons for hang-up, crash, etc...? > > Problem is, I can't estimate the load or amount of queries the > > application will generate, as I don't have much experience in this field > > and the DBs will grow over time. > > Should I implement ocf monitoring or rather not? > > I'm convinced you should ;-)
I'd agree. The oracle RA includes a similar check within the default, 0-level, monitor operation. Thanks, Dejan > Regards, > Andreas > > > > > I'm very thankful for any advice or hints about this matter, where to > > get more information, or personal experiences with the stability of > > mysql servers. > > Thanks > > Lino > > _______________________________________________ > > Linux-HA mailing list > > [email protected] > > http://lists.linux-ha.org/mailman/listinfo/linux-ha > > See also: http://linux-ha.org/ReportingProblems > > > _______________________________________________ > Linux-HA mailing list > [email protected] > http://lists.linux-ha.org/mailman/listinfo/linux-ha > See also: http://linux-ha.org/ReportingProblems _______________________________________________ Linux-HA mailing list [email protected] http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
