Hi Raiders,
I'm considering to purchase a 3Ware Escalade controller for a new server of
ours. I'm thinking of Escalade because of the infamous incompatibility
between Linux (2.2.x) SW RAID and LVM. And then there's the idea that maybe
the sophisticated elevator routines that make SCSI drives so much better in
JBOD setups are not so much better in a RAID setup if the controller has its
own elevator routines. Considering even that IDE drives are one third of the
price of SCSI drives in the same sequential performance class, it seems to
make a whole lot of economic sense to go with IDE RAID way.
So my question is this: are these thing reliable? I mean if I pull the plug
under several occasions, will the Escalade firmware handle the partial
writes to the stripes and mirrors, ie. will the block device be always
consistent? My reason to question this arises from criticism voiced here
earlier about the Escalade firmware. I have once tried to contact 3Ware
through a web form in their site but no answer yet.
The criticism mentioned above is from a message posted 2000-06-07 by Martin
Bene. Here's the relevant quote:
[start quote]
I've got three of these sitting on a shelf here; I'm not willing to risk
using them in a production system yet. The raid1 (mirroring) configuration
I'd want to use seems to have a rather nasty bug:
The firmware currently in use on the 3ware controllers does not catch
unclean shutdown in case of power loss, reset, kernel crash or whatever. If
a write is in progress during such an event, you'll get inconsistent data on
the disks - one will have new data already written, the other write may not
have finished. This is why software raid will do a compleat resync od data
on next startup in this case.
[end quote]
Martin then goes on to mention that he contacted 3Ware about the bug but
they said they had to concentrate on the new models forthcoming (the 6000
models just released, I suppose).
So if anybody knows whether the new models are reliable, please state your
experience.
Cheers,
// Jarkko Kniivil�, CTO, Ambient Factor
