Disk Recovery Part III

[Matthew Gillen]

Rich Braun wrote:
> Sure, you could take two 250Gb drives and create a 500Gb filesystem if that's
> the amount of data you have.  But if you have that much data, what conceivable
> scenario would prevent you from either (1) splitting the data into two
> separate filesystems, 
Because it's a hassle.  You'd think if you're dealing with that much
data you could find a way to organize it so that a filesystem barrier
wouldn't interfere.  But what if you guess wrong, and your organization
scheme stinks?  Then you spend (waste?) a bunch of time figuring out how
to balance the amount of data stored on each filesystem.

> or (2) shelling out the extra bucks to buy two 500Gb
> drives (or three 350Gb ones) and running RAID1/RAID5?
Because this is a home system, and I'm trying to recycle old disks that
aren't dead yet but whose primary purpose has been assumed by newer
disks.  Besides, once you get above a certain capacity, the price-per-MB
curve goes up a bit.

The big thing LVM buys me is that I can incrementally improve my system.
 I can buy a couple drives now, then in a year buy a couple more and
easily expand my system.  For home systems, buying everything you'll
ever want up-front is cost-prohibitive (for me anyway).  At the same
time, I don't know what my needs will be a year from now, and if I guess
I'll probably be wrong.

> If you're ever adding new material to the mp3/video collection, simply doing
> backups isn't enough to eliminate the questions "should I stripe?  should I
> mirror? should I just save money/time and ignore the problem?"
That decision will be different for different situations.  If money was
no object (ie I was setting something up for work), I'd probably buy
huge disks as you suggested.  If budget didn't allow for that, I'd have
to look closer at my options (LVM vs. multiple filesystems, 1 big fs vs.
a mirrored fs, etc) and see what was most appropriate.

--Matt