[linux-lvm] Feature Request (revert a logical volume back to its snapshot sta te)

[linux-lvm] Feature Request (revert a logical volume back to its snapshot sta te)

[Joe Harvell]

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I really love the snapshot logical volume feature, and I use it for 
making consistent backups of my system while it is running.

Recently, though I found myself wanting to use a snapshot logical volume 
to preserve the state of a filesystem while I experimented with 
changes.  When I needed to revert, I had to copy the contents from the 
snashot logical volume, destroy the snapshot and snapshot source, and 
then replace the snapshot source with the copy I made of the snapshot.

It seems like it would make sense for LVM to support a feature to revert 
the source logical volume to the state it was in when the snapshot was 
taken.  I read through all the man pages but I didn't see anything like 
this.  I realize it might not be possible to do this atomically while 
the source logical volume is active, but that's fine.  I would still 
like to be able to do it when the source is inactive.

---
Joe Harvell

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Re: [linux-lvm] Feature Request (revert a logical volume back to its snapshot sta te)

[Alasdair G Kergon]

On Fri, Feb 11, 2005 at 05:03:50PM -0500, Joe Harvell wrote:
> Recently, though I found myself wanting to use a snapshot logical volume 
> to preserve the state of a filesystem while I experimented with 
> changes.  When I needed to revert, I had to copy the contents from the 
> snashot logical volume, destroy the snapshot and snapshot source, and 
> then replace the snapshot source with the copy I made of the snapshot.
 
How about performing your tests on the snapshot device instead of the 
original?

Alasdair
-- 
agk@redhat.com

Re: [linux-lvm] Feature Request (revert a logical volume back to its snapshot sta te)

[Clint Byrum]

On Fri, 2005-02-11 at 22:50 +0000, Alasdair G Kergon wrote:
> How about performing your tests on the snapshot device instead of the 
> original?
> 

Snapshots are writable?!

-- 
Clint Byrum <cbyrum@spamaps.org>

Re: [linux-lvm] Feature Request (revert a logical volume back to its snapshot sta te)

[Jason Martin]

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On Fri, Feb 11, 2005 at 05:03:50PM -0500, Joe Harvell wrote:
> It seems like it would make sense for LVM to support a feature to revert 
> the source logical volume to the state it was in when the snapshot was 
I think it would also be handy to be able to 'roll back' a
filesystem.  Writing to the snapshot isn't always feasible since
the running application isn't in that place.  

-JM
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