is lvm deprecated?

[Chris Tyler]

On Sat, 2009-05-09 at 13:26 +0100, Timothy Murphy wrote:
> Mike Burger wrote:
> 
> > It's actually very simple and painless.
> 
> LVM is reasonably simple.
> 
> But in my view its disadvantages -
> particularly the difficulty of dealing with any kind of corruption -
> far outweigh its advantages.

I agree that corruption can be a huge issue for LVM, but it's really an
issue for any storage configuration, and needs to be dealt with using
other strategies.

> The main advantage - the ease with which partition sizes
> can be changed - is much less significant
> in this era of enormous disks.

On the contrary, I think that large disks make LVM even more valuable.

As one small example, LVM enables live migration -- moving from one disk
to another while a system is running. Back when we were dealing with
megabytes of data, the downtime needed to move those megabytes to
another disk was small. On a modern box, disks are in the terrabyte
range -- approaching a million times larger, but with transfer speeds
that are nowhere near a million times faster -- and it can take many
hours to migrate between disks. Being able to do that live greatly
reduces downtime (to perhaps a few minutes if the disks can't be
hot-plugged, or no downtime if the disks are hot-pluggable).

(It looks like volume management is moving down to the filesystem level.
This will be both good and bad; from an optimization point of view,
having the filesystem aware of the low-level storage details will be
valuable, but I cringe at the thought of having duplicated tools to do
volume management within each different filesystem type).

-Chris