Areca replacement; RAID rebuild (usually successful); backup; Areca
replacement with 3Ware controller or CoRAID (or JetStor) shelf; create
new RAID instance; restore from backup.
Let's just say we lost confidence.
gerry
Bruce Allen wrote:
What was needed to fix the systems? Reboot? Hardware replacement?
On Wed, 16 Apr 2008, Gerry Creager wrote:
We've had two fail rather randomly. The failures did cause disk
corruption but it wasn't an undetected/undetectable sort. They
started throwing errors to syslog, then fell over and stopped
accessing disks.
gerry
Bruce Allen wrote:
Hi Gerry,
So far the only problem we have had is with one Areca card that had a
bad 2GB memory module. This generated lots of (correctable) single
bit errors but eventually caused real problems. Could you say
something about the reliability issues you have seen?
Cheers,
Bruce
On Wed, 16 Apr 2008, Gerry Creager wrote:
We've used AoE (CoRAID hardware) with pretty good success (modulo
one RAID shelf fire that was caused by a manufacturing defect and
dealt with promptly by CoRAID). We've had some reliability issues
with Areca cards but no data corruption on the systems we've built
that way.
gerry
Bruce Allen wrote:
Hi Xavier,
PPS: We've also been doing some experiments with putting
OpenSolaris+ZFS on some of our generic (Supermicro + Areca)
16-disk RAID systems, which were originally intended to run Linux.
I think that DESY proved some data corruption with such
configuration, so they switched to OpenSolaris+ZFS.
I'm confused. I am also talking about OpenSolaris+ZFS. What did
DESY try, and what did they switch to?
Sorry, I am indeed not clear. As far as I know, DESY found data
corruption using Linux and Areca cards. They moved from linux to
OpenSolaris and ZFS, avoiding other corruption. This has been
discussed in HEPiX storage workgroup. However, I can not speak on
their behalf at all. I'll try to get you in touch with someone
more aware of this issue, as my statements lack of figures.
I think that would be very interesting to the entire Beowulf
mailing list, so please suggest that they respond to the entire
group, not just to me personally. Here is an LKML thread about
silent data corruption:
http://kerneltrap.org/mailarchive/linux-kernel/2007/9/10/191697
So far we have not seen any signs of data corruption on Linux+Areca
systems (and our data files carry both internal and external
checksums, so we would be sensitive to this).
Cheers,
Bruce
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Gerry Creager -- [EMAIL PROTECTED]
Texas Mesonet -- AATLT, Texas A&M University
Cell: 979.229.5301 Office: 979.862.3982 FAX: 979.862.3983
Office: 1700 Research Parkway Ste 160, TAMU, College Station, TX 77843
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