Hi Michael, Am 16.03.2010 00:23, schrieb Michael @ Professional Edge LLC: > Hello again Andreas, > > Interesting mix... assuming I follow your logic... you are suggesting > I mix the - "single non-clustered LVM mirror" with the "HA-LVM tag > based fail-over". yes. The other way is to use clustered-lvm which has the advantage of keeping its mirrors-state even when moving the volume(s) between nodes. In the setups I take care of, GFS(2) and concurrent access from both nodes is not a requirement and I like to be able to take a LV online without the cluster-framework. > > HA-LVM is where I started on this concept... so I have already setup > the basic /etc/lvm/lvm.conf - "volume_list = [ "VolGroup00", > "@`hostname`" ] type stuff for root mount only. > > When I looked at the LVM mirroring in general the concept of the > dedicated disk for mirror logging and/or use of memory made me > pause... but... you are saying do something like on node#1 - take > "shelf1: disk1" and LVM mirror it to "shelf2: disk1" - and put the > mirror logging in memory? true. lvcreate -m1 --corelog etc. > Therefore in a fail-over condition - I obviously loose the in memory > mirror logging - but node#2 would just see the LVM as in an > inconsistent state - and resync the mirror? Because of the lack of a logging-lun, LVM would always assume, that your devices are not in sync, so yes, it would sync everytime the LV is activated/moved between cluster-systems. If your LUNs are too large or you do not want the overhead, clvm is the way to go. Andreasw > > -Michael > > > Andreas Pfaffeneder wrote, On 3/15/2010 7:52 AM: >> Hi Michael, >> >> a way to prevent both system from thinking that they're responsible >> for the >> FC-devices is to use LVM for building a host-based-mirror and >> LVM-filter >> and -tags: >> >> - Set up your RHEL-Cluster >> - Modify /etc/lvm/lvm.conf: volume_list = >> ["local-vg-if-used-to-store-/","@local_hostname-as-in-cluster.conf"] >> (all >> systems of the cluster) >> - rebuild initrd, reboot >> --> LVM only accesses local LVs and LVs with the local hostname in the >> lvm-tag >> - create an mirrored lv with lvcreate --addtag or lvchange --addtag >> so the >> lv will be active on one system >> >> RH-Cluster supports floating LVs on its own, just add the LV + FS as >> resource. >> >> If you're not using a LUN for mirror-logging, your're moving the LVs >> from >> one system to the other at the cost of one full rebuild of the host >> based >> mirror. >> >> Regards >> Andreas >> -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
