[plug] Home Server LVM/RAID stuff

[Trevor Phillips]

I have a home server, and am living in the stone age, it seems - just
standard physical partitions. Adding disk is easy enough, but then the
new space is on a new mount point, no redundancy, running out of
space, yadda yadda...

Recently, a friend raved about how wonderful Windows Home Server was -
and it did sound quite impressive, what it was capable of. It's
motivated me to pull my finger out and try and do things better (and
safer) on my home server. However, my Linux server already does stuff
Windows Home Server never will - and this is the PLUG list - so I've
been reading up on similar Linux solutions.

There's basically two key features I'd really really like:

1) Being able to add more disk, and add that space to existing
partitions: LVM seems to fit this spot-on.
2) Being able to have data redundancy on SOME content, across drives,
in case of physical failure. Linux Software Raid sort of does this.

Now, really, only about 1/4 of my data I really need redundancy on.
You know, important stuff like photos, mail, tax documents, etc... All
the rest is typically regainable (ripped CDs/Video), or I wouldn't
shed too many tears over losing. So a full RAID1 config is way
overkill. Yes, disk is cheap, but the Wife won't necessarily buy that
argument. -_^

Back to Windows Home Server - this does both these tasks in one. You
can throw in more disk, have it add to volumes as you want, and you
can also tag content (I believe it's per FOLDER, not even per volume)
to keep a redundant copy on separate physical disks. It sounds like
doing all this, and changing the configuration, is a cinch.

So far, the best solution to me sounds like it involves creating 2
partitions (on separate disk, same size), RAID1ing them, and using
that for my important data, then using LVM for the rest of the less
important bulky data. Probably best to even use LVM with the RAID1 as
well.

I've read 2 ways of treating this LVM/RAID combo though - one was to
RAID the physical partitions, then create the LVM out of the resultant
raid partition. The other was to create 2 LVM logical partitions, in
separate groups, on separate disks, and RAID on top of that.

The former sounds neater, more efficient - but also sounds like it has
the old problem of being difficult to resize. I guess you could create
extra partitions later, RAID them separately, then add them to the LVM
of the first raid, but it seems tricky.

The latter sounds messier, but potentially easier to resize the raided
content later, since the RAID partitions are on LVM partitions, which
can be extended more easily.

What experiences have others had with setting up a similar setup? How
do these two solutions compare for performance & flexibility?

Are there any other neat solutions to do what I want? Ideally I wish
LVM could handle physical redundancy of a logical partition
automatically. If Microsoft can do it, why not Linux!

Thanks...

-- 
Trevor Phillips - http://dortamur.livejournal.com/
"On nights such as this, evil deeds are done. And good deeds, of
course. But mostly evil, on the whole."
 -- (Terry Pratchett, Wyrd Sisters)