[2514] in SIPB-AFS-requests
Enclosure for new AFS server's disks
daemon@ATHENA.MIT.EDU (Greg Hudson)
Fri Oct 25 13:24:15 1996
Date: Fri, 25 Oct 1996 13:23:36 -0400
From: Greg Hudson <ghudson@MIT.EDU>
To: sipb-afsreq@MIT.EDU
I've made arrangements with ASO to get a server-configuration sparc 5
in December so that we can replace ronald-ann during winter break. We
still need to buy disks for it. Fortunately, I have some time to
think about and discuss this before I was planning to make the
purchase.
As you're all aware, SIPB has had a lot of disk problems recently, as
has ASO. (ASO has probably had fewer failures for the amount of disks
they have, but they've still had quite a few.) We don't know why our
failure rate is so high, but there are several possibilities:
* Bad type of disk. This would be a reasonable explanation
looking at ASO's failures (they're almost all 2GB Barracudas
from Seagate), but SIPB has had Connor, Micropolis, and
Seagate disks fail (including a Seagate Hawk).
We have an order going through for five Fujitsu disks (for
other servers) on the theory that Fujitsu disks might have
better reliability. It will probably take a year or so to
decide whether this helps. In the meantime, I'd like to try
another axis.
* Bad arrangement (not spaced out well enough). A possible
explanation for SIPB's failures, but not for ASO's.
* Bad enclosures. We know that the R^2 half-height enclosures
are unacceptable, and that accounts for a lot of our recent
disk failures, but not all of them (and certainly not for
ASO's failures). It may be that the low-profile single-disk
enclosures sold by resellers don't provide enough airflow to
deal with modern disks, and we need something better.
I would like to try buying a multiple-disk enclosure for the new AFS
server's external disks. On Steve's recommendation, I wanted to try a
DEC Storageworks eight-disk enclosure, which he estimates would cost
about $400 (less than the cost of eight single-disk enclosures). We
can use the extra slots to house disks whose enclosures have gone bad.
Does this sound okay with people? I have not yet found a reseller
(maybe we can order directly from Digital) or a solid price (Steve got
his price information from ELI's, which is not really a preferrable
reseller for us).
As for the actual disks, I figured on buying four of whatever 4GB
disks the resellers recommend. Right now Falcon seems to be pushing
Quantum disks; I can ask specifically for Seagate or Micropolis disks
if people think that would be a good idea. I could get a mix of two
or three different kinds of disks, but I think we'd get better
information out of the experiment by picking four of the same kind of
disk.
