On Fri, Jun 13, 2008 at 12:25:31AM -0700, Joe Bill wrote: > >> I put the mysql datadir in /u/mysql and is ok. > >> but what about mysql.log, mysql.sock and mysql.pid > ? > >> they must be in the shared disk or each node have > >> their own copy in /var/lib/mysq ? > > > They should _not_ be on the shared disk. Some of > > them, such as mysql.pid, may even be used to > > check the status of the mysql resource. > > > > Dejan > > Dejan, would please elaborate why the ".log", ".sock", > ".pid" should not be on the shared disk ?
All these files belong to the mysql instance running on that node, i.e. they are "local" by nature. A shared disk may be visible on another node and this data makes no sense over there. Is that reason good enough? > My reasoning is that if the shared (data) disk is > down, what difference does it make that the RA returns > an error saying it can not access the ".pid" file or > that the RA returns an error saying it can not acces > the data files ? > > An argument in favor of having the ".pid" and ".log" > (the ".sock" being the exception as it is solely used > for local communication) on the same disk is that, in > essence, for a given instance, these files should be > *unique*, whatever the host the instance is running > on. > > If this appears more self-evident for the ".log" file, > for the pid file, it is precisely because there is no > pid file, and some other conditions, that a RA on a > node taking over a failed node, can assert that an > instance was cleanly stopped. > > If each node has it's own ".pid" file for one same > instance on local storage, there is no way the other > nodes can access the .pid file on a node that has just > failed. This may not appear as immediately critical, > but it becomes critical when the failing node with the > leftover pid file is bound to take over an instance. > > > > > > _______________________________________________ > 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
