Many thanks to:
Gary Jenkins: gcjenkins_at_escocorp.com
David DeWolfe: sxdjd_at_ts.sois.alaska.edu
Joseph M. Dunleavy: dunleavj_at_labs.wyeth.com
and all others in the same boat as I am.
But NOT to:
Oracle
My original posting:
>Oracle is pointing to a hardware problem, I'm not seeing any. Has
>anyone seen this Oracle error message before?
>
>
>
>WARNING: DBWR failed to complete async write within 186 seconds
>Thu Jul 17 07:55:57 1997
It turns out that several people have seen this problem. But almost no
one had any resolution from Oracle.
I have not found the definitive answer for my specific scenario (DU
3.2g, Oracle 7.3.2.3, Alpha Server 8400, UFS Filesystems),
but have found a few key points that are worth looking at.
1) About half of the errors occurred within 10 minutes to 2 days before
a UFS filesystem reached 100%.
Oracle (after I found this loose connection) told us that this
is the problem.
2) It was pointed out by someone on the mailing list, that DU does not
support asynchronous I/O on UFS or AdvFS filesystems.
This would explain the async failure.
3) Running multiple DBWR under this environment, can cause contention
and fail one or more instances of the DBWR.
4) Oracle support, via several people that I've heard from, has always
referred this problem to a hardware issue. Yet, they have
yet to give a firm resolution. We were told "full filesystem"
another was told "processor too busy" another that they needed
to upgrade to Oracle 7.3.3, and yet another was told that there
was a patch for this for 7.3.2.3 (but the patch was vaporware).
(Are we actually paying for this support?)
5) Recompiling the executables and/or reinstalling Oracle will not help.
To sum up my discoveries, a short term solution is to reduce the number
of DBWR to 1 and keep a very close eye on filesystem use.
For the longer term (which is what we were beginning to plan on
doing) is upgrade to DU 4.0 and Oracle 7.3.3 with patches for both.
But above all, take everything Oracle support says with a grain
of salt (and a shot of tequila).
I hope this makes this issue as clear as mud for all curious.
-Paul
>From the dark land of the mole people
Received on Wed Sep 03 1997 - 21:54:52 NZST