On Wed, Jul 11, 2012 at 03:06:19PM +0000, Stefan Schloesser wrote: > My Idea is to use GlusterFS as a replicated filesystem (for apache) and > built-in mysql replication for the database. In the event of a failure > I need to run a script to implement an ip switch. To switch IP for what? glusterfs in replicated mode, using the native (FUSE) client, doesn't need this. The client talks to both backends, and if either backend fails, it continues to work. > How should I monitor such a system? I'm not sure if there's a proper API. As a starting point, try running 'gluster volume status' as root and parsing the results. e.g. here the bricks on one server are unavailable: $ sudo gluster volume status Status of volume: safe Gluster process Port Online Pid ------------------------------------------------------------------------------ Brick dev-storage1:/disk/storage1/safe 24009 N N/A Brick dev-storage2:/disk/storage2/safe 24009 Y 1710 NFS Server on localhost 38467 Y 2034 Self-heal Daemon on localhost N/A Y 1736 NFS Server on 10.0.1.1 38467 Y 1631 Self-heal Daemon on 10.0.1.1 N/A Y 1637 Status of volume: fast Gluster process Port Online Pid ------------------------------------------------------------------------------ Brick dev-storage1:/disk/storage1/fast 24010 N N/A Brick dev-storage2:/disk/storage2/fast 24010 Y 1720 NFS Server on localhost 38467 Y 2034 NFS Server on 10.0.1.1 38467 Y 1631 Status of volume: single1 Gluster process Port Online Pid ------------------------------------------------------------------------------ Brick dev-storage1:/disk/storage1/single1 24011 N N/A NFS Server on localhost 38467 Y 2034 NFS Server on 10.0.1.1 38467 Y 1631 Status of volume: single2 Gluster process Port Online Pid ------------------------------------------------------------------------------ Brick dev-storage2:/disk/storage2/single2 24011 Y 2028 NFS Server on localhost 38467 Y 2034 NFS Server on 10.0.1.1 38467 Y 1631 It would be neat if this could be integrated into SNMP. There are some good tools I found which provide a framework to integrate mdraid and smartctl status: http://www.mad-hacking.net/software/index.xml http://downloads.mad-hacking.net/software/ It should be relatively straightforward to add gluster into this. > Does Gluster provide an integration > with corosync as a resource? Not that I'm aware of, as far as I can see it's not needed. Volume status information is synchronised between the peers in the cluster using some internal protocol, and I'm not exactly sure how it deals with split brain scenarios. Another project which *does* use corosync is sheepdog. This is completely different to glusterfs though - it's a distributed block level store for KVM. > I guess it is not a good idea to keep the mysql data files on the > glustered fs, or is that feasible? I'd say that's definitely a bad idea, especially if you had two different mysqld's talking to the same storage. Regards, Brian.
