RE: 10G and UFS - long write times
- From: "Jesse, Rich" <Rich.Jesse@xxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Thu, 8 Jun 2006 11:13:08 -0500
Run away from UFS as fast as you can. If your mountpoints are of any
size (400GB+) and your system crashes (hypothetically, let's say your
A/C fails and 3 months later all sorts of wierd hardware issues crop up,
probably from the heat stress), you could see reboot times measured in
hours or days due to the fsck'ing of UFS.
There's probably some handy MP options in UFS you could use, like
nodiratime, noatime, etc., but do yourself a favor and migrate off of
UFS. We went with Veritas, and have been much happier. Yes, there is
the occasional reboot because it won't let go of a failed drive, despite
being hotswappable, but it's muuuuuuuch better than UFS. I haven't had
the opportunity to play with the newer ZFS yet and since you're not on
Solaris 10, I don't think it wouldn't be an option for you.
GL!
Rich
________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Hallas, John, Tech
Dev
Sent: Thursday, June 08, 2006 3:16 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: 10G and UFS - long write times
We are seeing big problems when issuing disk writes using 10G (both 10.1
and 10.2). Reads are not an issue
Very difficult to track down the exact combination but so far it looks
as if it is a combination of 10G and local disk mounted using UFS .
V440 Solaris servers could also come into the combination because that
is what I have done a lot of the testing on as that is what is
available. I have now tested on around 10-12 servers with consistent
findings.
The test is very simple and quick to do. Searching Metalink and WebIV
does not give any clues. I am about to log a tar but I know I will
require all sorts of Unix information which is quite long-winded for me
to get so any help would be appreciated.
The test
CREATE TABLE test( a number, b CHAR(2000) )tablespace xxxx ;
Set timing on
BEGIN
FOR r IN 1..50000 LOOP
INSERT INTO test (a,b) VALUES (r, 'test');
COMMIT;
END LOOP;
END
On SAN disk and 9i on local UFS mounted disk I am seeing response times
from 0:15 to 0:30 seconds
On 10G on San I see the same
On 10G using local UFS disk the time various from 7:00 to 9:00 minutes
and is very repeatable.
I have tried around 10 servers now and the results are consistent.
Whilst we have quite a few 10G installations, not many are on local disk
and the majority are on Sun 440 (2.9 OS) so my results may indicate a
UFS problem when it could be an OS one (or an Oracle one of course). OS
writes to disk are stable at twice as fast on San as local disk and the
fact that 90i does not show a problem seems to take away the OS part out
of the equation. But nothing is certain yet.
PS the waits are all IO related - log buffer , log file sync etc
Thanks for any help
John
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