Re: [gentoo-user] LVM (Was: the best filesystem for server: XFS or JFS (or?))

[Joost Roeleveld]

On Thursday 24 March 2011 12:19:39 Dale wrote:
> J. Roeleveld wrote:
> > On Thu, March 24, 2011 12:30 pm, Volker Armin Hemmann wrote:
> >> On Thursday 24 March 2011 08:49:52 J. Roeleveld wrote:
> >>> On Wed, March 23, 2011 5:43 pm, Volker Armin Hemmann wrote:
> >>>> md raid devices can do barriers. Don't know about lvm. But lvm is
> >>>> such
> >>>
> >>> a
> >>>
> >>>> can
> >>>> of worms I am surprised people still recommend it.
> >>>
> >>> What is wrong with LVM?
> >>> I've been using it successfully without any issues for years now.
> >>> It does what it says on the box.
> >>
> >> it is another layer that can go wrong. Why take the risk? There
> >> are enough cases of breakage after upgrades - and besides snapshots...
> >> is the
> >> amount of additional code running really worth it? Especially with
> >> bind
> >> mounting?
> >
> > There are always things that can go wrong and I agree, adding additional
> > layers can increase the risk.
> > However, the benefits of easily and quickly changing the size of
> > partitions and creating snapshots for the use of backups are a big
> > enough
> > benefit to off-set the risk.
> >
> > Bind-mounting is ok, if you use a single filesystem for everything. I
> > have partitions that are filled with thousands of small files and
> > partitions filled with files are are, on average, at 1GB in size.
> > I haven't found a filesystem yet that successfully handles both of these
> > with identical performance.
> > When I first tested performance I found that a simple "ls" in a
> > partition
> > would appear to just hang. This caused performance issues with my
> > IMAP-server.
> > I switched to a filesystem that better handles large amounts of small
> > files and performance increased significantly.
> >
> > The way I do backups is that I stop the services, create snapshots and
> > then restart the services.
> > I then have plenty of time to backup the snapshot.
> > If I were to do this differently, I'd end up having a downtime for over
> > an hour just for a backup.
> > Now, it's barely a minute of downtime.
> >
> > That, to me, is a very big bonus.
> >
> > --
> > Joost
>
> I have never used LVM but when it messes up after a upgrade, as has
> happened to many others, see if you say the same thing.  I hope your
> backups are good and they can restore.
>
> Dale
>
> :-)  :-)

Backups are good and I can restore.
Usually need them when I mess things up and accidentally delete files I wanted 
to keep....

LVM may mess up if something goes wrong, but as the LVM-tools backup the 
metadata for LVM, it is trivial to restore and I have not lost any data 
because of issues like that. :)

--
Joost