Redhat, LVM users,
I recently set up a software RAID-1+0 array with mdadm on a Redhat ES 4.1
system where the array contained a single logical volume (LVM2). What I
noticed is that when the system booted it wouldn't see this volume or of course
any of the file systems in it.
I did some poking around and I found this clause in /etc/rc.d/sysinit.rc:
if [ -f /etc/raidtab ]; then
# Add raid devices
[ -f /proc/mdstat ] || modprobe md >/dev/null 2>&1
if [ -f /proc/mdstat ]; then
echo -n $"Starting up RAID devices: "
...
# LVM2 initialization, take 2
if [ -c /dev/mapper/control -a -x /sbin/lvm.static ]; then
if /sbin/lvm.static vgscan > /dev/null 2>&1 ; then
action $"Setting up Logical Volume
Management:" /sbin/lvm.static vgscan --mknodes --ignorelockingfailure
&& /sbin/lvm.static vgchange -a y --ignorelockingfailure
fi
fi
# LVM initialization, take 2 (it could be on top of RAID)
if [ -e /proc/lvm -a -x /sbin/vgchange -a -f /etc/lvmtab ]; then
action $"Setting up Logical Volume Management:"
/sbin/vgscan && /sbin/vgchange -a y
fi
fi
fi
Of course with the new mdam RAID arrays in RH ES 4.1 there is no
/etc/raidtab, so the first
then clause above is never entered. This means that the logical
volume on my RAID-1+0 array is
never found as the array isn't available when the first check for
logical volumes is done in /etc/rc.d/sysinit.rc.
This looks like a bug to me. My solution was to force a check for
logical volumes after the
above clause by adding this to /etc/rc.d/sysinit.rc:
if /sbin/lvm.static vgscan > /dev/null 2>&1 ; then
action $"Jed's Logical Volume Management setup:"
/sbin/lvm.static vgchange -a y --ignorelockingfailure
fi
That seems to work and I believe it is otherwise harmless, though it
might be a bit brute force.
I just wondered if anybody else has run into this problem or heard of
any other solutions.
Incidentally, while working on this problem I noticed that if after a
reboot if I executed:
#/sbin/lvm.static vgchange -a y --ignorelockingfailure
the volume still was not visible or set active. However, if I did
#/sbin/lvm.static vgscan
first and then
#/sbin/lvm.static vgchange -a y --ignorelockingfailure
the volume and its file systems show up. That seems to me like a
failure in vgchange.
I would think it should effectively do a vgscan before setting all
the volumes active if
it is run on all volumes. Perhaps this doesn't reach the level of a
bug, but it was
counter intuitive to me.
--Jed http://www.nersc.gov/~jed/
--Jed http://www.nersc.gov/~jed/
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