Am 29.11.2011 05:10, schrieb Michael Mol:
> I've got four 750GB drives in addition to the installed system drive.
> 
> I'd like to aggregate them and split them into a few volumes. My first
> inclination would be to raid them and drop lvm on top.  I know lvm well
> enough, but I don't remember md that well.
> 
> Since I don't recall md well, and this isn't urgent, I figure I can look
> at the options.
> 
> The obvious ones appear tobe mdraid, dmraid and btrfs. I'm not sure I'm
> interested in btrfs until it's got a fsck that will repair errors, but
> I'm looking forward to it once it's ready.
> 
> Any options I missed? What are the advantages and disadvantages?
> 
> ZZ
> 

Sounds good so far. Of course, you only need mdraid OR dmraid (md
recommended). What kind of RAID level do you want to use, 10 or 5? You
can also split it: Use a smaller RAID 10 for performance-critical
partitions like /usr and the more space-efficient RAID 5 for bulk like
videos. You can handle this with one LVM volume group consisting of two
physical volumes. Then you can decide on a per-logical-volume basis
where it should allocate space and also migrate LVs between the two PVs.

Another thing you can think of is whether you want encryption. I've done
this for my laptop. The usual setup would by md->lvm->crypt. I've done
it crypt->lvm (an LVM physical volume on top of an encrypted partition).
This way, I only need to enter the password once. You can enforce a
specific order between lvm, md and dmcrypt by putting stuff like this in
/etc/rc.conf:
rc_dmcrypt_before="lvm"
rc_dmcrypt_after="udev"

Regards,
Florian Philipp