Re: Software RAID and drive failures
Ron Johnson said:
> Hmmm. By definition, RAID1 is "mirroring". Never heard of putting any
> more than 2 disks in a mirrorset. Never even thought of it,
> actually. With more than 2 disks, I'd automatically go with RAID5.
in many cases I would too. However, most implimentations of LILO
and or GRUB cannot boot from a software raid 5 array. A lot of
systems I have worked with[1] usually only have enough space for
2 or 3 properly cooled drives(you could fit a 4th, but usually
in a spot where it does not have active cooling). As a result
I like to use PC Power & Cooling's Bay Cool III. Takes 2 5.25"
drive bays, and can fit 3 disks in there. Has 1 real big powerful
fan in front of all 3 disks(more reliable then those tiny ones),
and a nice removable filter(I'm a big fan of having a LOT of
active cooling)
On such systems I usually go with 2 disk raid 1 with a hot spare
for maximum reliablity. Since there is no room for a 4th disk
for a boot device and the Debian version of LILO/grub doesn't
appear to support booting from raid 5 last I checked, raid 1 is
the only option. I don't want to waste a drive, so I make the 3rd
disk hot spare. If the system has a 3rd 5.25" bay it usually gets
the CDROM. Otherwise I use an external SCSI cdrom for any
cdrom needs.
Somehow SuSE has a version of LILO/GRUB that can boot a raid 5
volume without any trouble(same configuration as above, 3 disks
and one raid 5 array). Not sure how they do it. When I tried it
on debian LILO refused to even load in the MBR, saying something
like 'lilo only supports root on raid 1' or something.
nate
[1] http://portal.aphroland.org/~aphro/rackmount.jpg <- example of such system.
Reply to: