[KLUG Members] Moving a HDD

[Phillip Hofmeister]

On Mon, 16 Aug 2004 at 09:47:08AM -0400, Rusty Yonkers wrote:
> > Did he use LVM?  If not, no.
> 
> What is LVM?

Logical Volume Management.

I have never implemented it, but here is the idea.

I have a hard drive which I partition up and set up my filesystem on.  I
decide to set it up using LVM.  2 years down the road I say "Oh sh*t,
/home isn't big enough".  I throw another HDD into the computer and I
can (hot and on the fly) add a new physical partition ("extent") to the
logical volume and get more space on the fly.  The down side to this, of
course, is as you add more hard drives your chance of failure
increases.

Let's assume you MTBF per hard drive is 5 years.  If I use LVM and have
2 hard drives I can expect to have a failure every 2.5 years, versus the
5 I would have with 1 drive.

You could (of course) make the "physical extents" RAID sets.  This would
provide a level of redundancy against failure.  In other words, rather
than adding a second hard drive, I add a second raid set to the Logical
Volume.

Hope this helps,

-- 
Phillip Hofmeister