[Fed-Talk] Apple Software RAID (was G5 power supply capacity?)
[Fed-Talk] Apple Software RAID (was G5 power supply capacity?)
- Subject: [Fed-Talk] Apple Software RAID (was G5 power supply capacity?)
- From: David Emery <email@hidden>
- Date: Thu, 10 Jul 2008 09:43:48 -0400
I have a G5/2ghz DP, with a SeriTek 1S2 SATA card and an add-on 'rack'
holding 2 extra drives. This has 4 500gb SATA drives in it, formatted
as 2x500gb RAID Mirrored sets. As I think I mentioned before, one set
was coming up with only 1 drive in it, and the other set was not coming
up at all on the desktop/Disk Utility (although RAIDeye could see this
2nd RAID set.) I thought I was hearing click-of-death in one drive.
Sure enough, when I pulled the dead drive from the G5's 'native' 2nd
drive slot and moved a drive from the add-on rack back to this slot,
-both- RAID sets came up. One came up with both members intact, and the
other came up indicating only 1 drive was present.
Three observations:
1. A dead drive can mess up more than just its own RAID set
2. It appears that the -ordering- of drives in a RAID set is
significant. If the first drive is down, the RAID set seems to have
more problems than when the 2nd drive (as shown in the Disk Utility RAID
tab) is down.
3. RAID Mirrored saves your posterior... (This is the 2nd or 3rd
time I've had a drive go down where the data was RAIDed, with no loss of
data but some manual drive reconfiguration actions...)
I've seen comments that say you cannot RAID drive partitions. That's
not my experience. On another machine, I've partitioned 320gb drives
into 50gb & 270gb partitions, and then RAIDed them together. This works
fine on Tiger (I haven't tried it on Leopard.)
I sure wish Apple would make a lower-end desktop that can hold at least
2 drives, preferably 4. A G4/933 makes a reasonable file server,
holding 4 drives (if you add a 2nd IDE or SATA drive). The only problem
with that machine is a slow internal bus.
One more comment: I've had very good luck with an external FW800 RAID
enclosure, the "Venus DS3R". This holds 2 IDE drives (max 750GB) and
has onboard RAID. The case cost me about $150. The only point on this
box is that you need to first install and configure the enclosure for 2
separate hard drives. Format each drive independently. Then you can
change the DIP switches to RAID Mirrored, and let the box sit and
'crank' for a day to construct the RAID Mirrored pairing. This
enclosure is about the size of a 5.56mm Ammo Can, complete with a handle
on top. It also has 2 removeable disk trays, although they're a bit
fragile (I broke the plastic handle on one.) I mention this as an
excellent option for very reliable removable storage (that could be
easily locked up on a safe, for instance.) Because it's FW800, it's
pretty fast and could well be used as the boot drive for classified
processing (not that I do any of that in my home office...)
dave
--
David Emery, DSCI, supporting PdM FCS (BCT) SW Integration
703 298 3473 (office/cell), 703 272 7496 (fax)
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