Subject: Re: how to bring a mounted filesystem to an almost clean state?
To: Daniel Carosone <firstname.lastname@example.org>
From: Christian Limpach <email@example.com>
Date: 02/15/2003 15:55:27
Quoting Daniel Carosone <firstname.lastname@example.org>:
> Even without addressing the filesystem issues at the layer above,
> I'd be interested in such a device. Is this something you'll be
> able to release when you're done?
Yes. The driver is available as an LKM for 1.6_STABLE. I have a pkgsrc
package which builds the LKM and includes some rc.d files to load it early
enough, before fsck wants to run:
There's only a very rough setup tool included, you almost definitely want to
get some volume manager software.
> At the upper layer, it's probably something that will need direct
> support from the filesystems. In the softdep case, something that
> can be inserted in the dependency chain as a barrier - and when it
> finally hits the lower layer device in order, it triggers the actual
> snapshot to happen. That should avoid the need for locking, which
> you need to avoid so your snapshots remain transparent.
is there really such a single ordered dependency chain (in the softdep case)
and does it include non-metadata accesses?
Christian Limpach <email@example.com>