After having a bit of a fiasco with clvmd, I would like to start from scratch, and really not use clvmd, since in my case its almost not needed. I can easily have 'lvscan' incorporated in higher management things like ... puppet.
In any case, how does one fix the:
connect() failed on local socket: No such file or directory
Internal cluster locking initialisation failed.
WARNING: Falling back to local file-based locking.
Volume Groups with the clustered attribute will be inaccessible.
Would fdisk /emcpowerpath, pvcreate /emcpowerpath, and recreating the VG fix this issue?
I've been dealing mostly with iSCSI with EMCs (Celerra), not FC; and I haven't used Cluster LVM. LVM maintains (iirc) 386kb of metadata at the beginning of a PV, and the rest is raw data.. so chances of losing data is slim (if you can tolerate some downtime).. you can use dmsetup to get raw disk location information beforehand for each LV, in case it's required.
I've been using straight LVM across 80+ node clusters without a problem, using higher level tools to stop concurrent access to the same LVs. I also don't do any automatic metadata changes.. Additions of new LVs is also OK, so long as vgscan is run on all nodes afterwards (and on the node you're making the change beforehand too).. but the ideal situation is to pre-allocate all LVs.