root filesystem snapshots

in the past i have read a number of posts related to problems with doing snapshots of logical volumes that contain the root filesystem. i am able to replicate the problem here as well, the system just hangs. can anyone tell me specifically what the problem relates to and if there is a fix available? i have downloaded the latest LVM2 source and there is no mention of it in WHATS_NEW.

i would like to warn people should they decide to do a snapshot of a logical volume that contains the root filesystem. under what circumstances will i run into this problem?
is it a certain level of LVM?
a certain level of the kernel?
a certain level of device-mapper?
a certain filesystem type?

also, i have seen problems with doing snapshots of filesystems using ext3. i assume this is related to the VFS lock patch. should i be able to perform snapshots of ext3 filesystems without failure?

Simply not supported yet.

Some changes in WHATS_NEW move towards supporting it - in particular a kernel with headers supporting the O_NOATIME change in 2.00.23 is a pre-requisite.

Alasdair

[email protected]

is only not supported with LVM2? i am almost certain this worked with earlier versions of LVM.

sorry to be a pest about this, but can anyone tell me what the criteria for snapshots on root to fail?

all LVM2?
LVM2 with 2.6 kernel only?