Mark Allums put forth on 4/27/2010 10:31 PM:
For DIY, always pair those drives. Consider RAID 10, RAID 50, RAID 60,
etc. Alas, that doubles the number of drives, and intensely decreases
the MTBF, which is the whole outcome you want to avoid.
This is my preferred mdadm 4 drive setup for a light office server or home
media/vanity server. Some minor setup details are omitted from the diagram
to keep it simple, such as the fact that /boot is a mirrored 100MB partition
set and that there are two non mirrored 1GB swap partitions. / and /var are
mirrored partitions in the remaining first 30GB. These sizes are arbitrary,
and can be seasoned to taste. I find these sizes work fairly well for a non
GUI Debian server.
md raid, 4 x 500GB 7.2K rpm SATAII drives:
mirror mirror
/ \ / \
-------- 3 -------- -------- 3 --------
| /boot | 0 | /boot | | swap1 | 0 | swap2 |
| / | G | / | | /var | G | /var |
|--------| |--------| |--------| |--------|
| /home | | /home | | /home | | /home |
| /samba | | /samba | | /samba | | /samba |
| other | | other | | other | | other |
| | | | | | | |
| | | | | | | |
-------- -------- -------- --------
\ \ / /
-------------------------------
RAID 10
940 GB NET
For approximately the same $$ outlay one could simply mirror two 1TB 7.2K
rpm drives and have the same usable space and a little less power draw. The
4 drive RAID 10 setup will yield better read and write performance due to
the striping, especially under a multiuser workload, and especially for IMAP
serving of large mailboxen. For a small/medium office server running say
Postfix/Dovecot/Samba/lighty+Roundcube webmail, a small intranet etc, the 4
drive setup would yield significantly better performance than the higher
capacity 2 drive setup. Using Newegg's prices, each solution will run a
little below or above $200.
This 4 drive RAID 10 makes for a nice little inexpensive and speedy setup.
1TB of user space may not seem like much given the capacity of today's
drives, but most small/medium offices won't come close to using that much
space for a number of years, assuming you have sane email attachment policies.