[Linux-cluster] Clustered VGs with many PVs slow to activate

[Janne Peltonen]

Hi.

There is a clustered vg in my five-node cluster (four of which have
access to the SAN where the physical devices reside). It seems to me
that the more LV's and PV's I've got, the more time it takes to get the
VG activated. When I had 8 PV's and 79 LV's, it took some ten minutes to
activate the VG on each node. Now, I extended the VG by 39 PV's (so that my
sometimes-disk-intensive services wouldn't interfere with each other,
each has its own 'disk' from the SAN) and I haven't succeeded in
activating the VG anymore. (I did the pvcreates on one node, and they
were fast. Thereafter I run the vgextend on the same node, and it took a
couple of minutes. Then I tried to do vgdisplay on one of the other
nodes, and got an error (the lvm couldn't find the new PV's and then,
the VG itself). I rebooted all the nodes but they haven't booted
yet. The cluster seems to be up, and the nodes have all successfully
started CLVMD (I'm seeing this from our remote syslog host, I don't have
access to the node consoles right now (stupid java remote consoles
and stupid JVMs that don't handle slow X11 connections well)) - and
that's it. They are all probably trying to activate the VG with 47 PV's,
and it seems to take ages.  It started an three-quarters of an hour ago,
and now I'm going to sleep (it's midnight here) and see if it'll be up
by tomorrow morning...


--Janne
-- 
Janne Peltonen <janne.peltonen at helsinki.fi>