using LVM on a cluster
Hi.
I am in the process of setting up a small 2-node HA cluster (for NFS,
active/passive) with a shared disk for storage. Because Corosync and
pacemaker look nice and good, I am trying to make it work with this
combination instead of cman, which is what clvm is compiled for in Debian.
There are a couple of howto's on the web on recompiling the lvm package
with Openais or Corosync , so that's what I did. However, I'm still
confused about the relationship between the cluster manager and the lock
manager. If I understood right, this is the correct order in which
things will be started:
* start Corosync (or openais, if clvm is compiled with openais support
instead)
* you need to run some kind of resource manager
* the resource manager (pacemaker) must have a resource defined that is
the dlm controld - I tried starting dlm_controld at the command line,
this seems to make clvm happy but unfortunately that command has no man
page.
* then, a bunch of files appear in /sys/kernel/config/dlm
Actually, that controld should be started by the cluster resource
manager is also something I just read on the web, and it sounds kinda
odd to me. After all, you need to run an instance on every cluster node
that accesses shared storage, right?
[[I also tried the same thing but with a clvm compiled for openais, I
read it uses another lock manager ("Lck") but I'm not sure if and how
this one is actually cluster-aware since it doesn't seem to rely on a
resource defined in the cluster.]]
[[Another thing that I find rather strange is that corosync is started
waaaay at the end of the boot process, and clvm is started at the
beginning, even if I changed the dependency of 'cman' to 'corosync' in
clvm's init script. (clvm is started in rcS.d). But that's got more to
do with lsb init scripting than with clustering, I suppose.]]
If anyone could make me wiser or more educated about any of this, I'd be
grateful :-)
--
No part of this copyright message may be reproduced, read or seen,
dead or alive or by any means, including but not limited to telepathy
without the benevolence of the author.
Reply to: