[linux-lvm] root filesystem snapshots

[linux-lvm] root filesystem snapshots

[rich turner]

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?

Re: [linux-lvm] root filesystem snapshots

[Alasdair G Kergon]

On Tue, Jan 04, 2005 at 02:19:51PM -0800, rich turner wrote:
> in the past i have read a number of posts related to problems with doing
> snapshots of logical volumes that contain the root filesystem. 

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
-- 
agk@redhat.com

Re: [linux-lvm] root filesystem snapshots

[rich turner]

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

On Tue, 2005-01-04 at 14:32, Alasdair G Kergon wrote:
> On Tue, Jan 04, 2005 at 02:19:51PM -0800, rich turner wrote:
> > in the past i have read a number of posts related to problems with doing
> > snapshots of logical volumes that contain the root filesystem. 
> 
> 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

Re: [linux-lvm] root filesystem snapshots

[rich turner]

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?

On Tue, 2005-01-04 at 14:59, rich turner wrote:
> is only not supported with LVM2? i am almost certain this worked with
> earlier versions of LVM.
> 
> On Tue, 2005-01-04 at 14:32, Alasdair G Kergon wrote:
> > On Tue, Jan 04, 2005 at 02:19:51PM -0800, rich turner wrote:
> > > in the past i have read a number of posts related to problems with doing
> > > snapshots of logical volumes that contain the root filesystem. 
> > 
> > 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
> 
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