Hey Kevin,
My Oracle Perf Tuning instructor suggested doubling the LOG_BUFFER until the
requests get under control. Problem is that each bump requires a reboot.
Since ours was severe enough, I went from 1MB to 4MB. When that wasn't
enough, I went to 12MB. This is over the course of almost 12 months, due to
uptime requirements.
This is fine unless your rego log files are in contention with other
datafiles (archives, datafiles, controlfiles) in the database. A larger
LOG_BUFFER may help, but it's just a workaround for the underlying problem.
For now, our whole shmear is on an HP AutoRaid. I know, I know. It seemed
like a good idea at the time (before Oracle training). I'm seeing LGWR
write times up to over a second at peak. Not only that, but even with a
LOG_BUFFER of 12MB in a 500MB total SGA w/175 users, I'm getting almost 3000
redo space requests per week. Ouch.
Oh, to be able to use Loney's 15-drive setup. Hell, I'm not asking for 22!
BTW, I'm on 8.0.5.2.0 on HP/UX 10.20. Next week is HP/UX 11.0, with 8.1.7
and an extra RAID0 for my redos to follow. Yay!
Good luck!
Rich Jesse System/Database Administrator
[EMAIL PROTECTED] Quad/Tech International, Sussex, WI USA
> -----Original Message-----
> From: Kevin Kostyszyn [mailto:[EMAIL PROTECTED]]
> Sent: Friday, March 23, 2001 14:06
> To: Multiple recipients of list ORACLE-L
> Subject: RE: Log Buffer
>
>
> yes, I think that does help. I am thinking I am going to
> make them larger?
> 21 requests
>
> -----Original Message-----
> Sent: Friday, March 23, 2001 2:46 PM
> To: 'Kevin Kostyszyn '
>
>
> Hi...
>
> I don't think so...
>
> you must adjust your LOG_BUFFER acoording to:
>
> select substr(name,1,25) Name,
> substr(value,1,15) "VALUE (Near 0?)"
> from v$sysstat
> where name = 'redo log space requests';
>
> Hope this help!
>
> -----Original Message-----
> To: Multiple recipients of list ORACLE-L
> Sent: 3/23/01 8:35 AM
>
> Hello DBA's
> You know, I read somewhere that you can make your log_buffer 10
> percent of
> your total sga. So if you had a 500mb sga you could have a 50 mb
> log_buffer? What do you guys think, the illustrious Ross doesn't like
> such
> large log_buffers.
>
> Sincerely,
> Kevin Kostyszyn
> DBA
> Dulcian, Inc
> www.dulcian.com
> [EMAIL PROTECTED]
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