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Home -> Community -> Usenet -> c.d.o.server -> Re: HELP: RAID-5 Killing Performance
Jonathan Lewis wrote:
>
> Switch on timed_statistics before you
> do anything else. Then check v$system_event
> to find out where you lose most time. Also
> check volume and average write times for
> data, temp, rbs, and redo before worrying about
> whether you should change the configuration.
>
> It is probably not sensible to archive direct to
> tape - (a) it's hard to manage changing the tapes
> in a timely fashion, (b) writing to tape is usually
> much slower than writing the redo log so you would
> end up tape-bound and (c) tapes are more error
> prone than discs.
>
> --
>
> Jonathan Lewis
> Yet another Oracle-related web site: http://www.jlcomp.demon.co.uk
>
> In2Home User wrote in message
> <937333485.18113.0.pink.d4e11496_at_news.in2home.co.uk>...
> >We're running Oracle 8.0.5 on Solaris 2.6.
> >Our database server is a Sun UltraSparc I 333MHz with 1GB of RAM.
> >We have several disks, a RAID-5 array, and a local tape device.
> >
> >My DBA is utilizing the disks in the following manner:
> >
> >disk1 - os
> >disk2 - home
> >disk3 (mirrored) - archived redo logs
> >disk4 (RAID-5) - control file, system, temp, oracle software
> >disk5 (RAID-5) - control file, rbs, redo logs
> >disk6 (RAID-5) - control file, tools, users, redo logs
> >
> >My largest concern is that having the redo logs on RAID-5 has
> >got to be killing my performance. Ideally, they should be on a
> >dedicated set of mirrored drives (then again, ideally I should have
> >22 separate disks, yeah). However, my DBA feels that its more
> >important to have the archive logs on the dedicated mirrored disks.
> >
> >Anyone care to share their opinion as to how we might make better
> >use of the above hardware setup? Would it make sense to write archive
> >logs directly to tape and move the redo logs to the mirrored disks?
Hello Johnathon,
On the topic of timed_statistics, I have this:
(From the Oracle doco)
"If TIMED_STATISTICS is FALSE, the statistics related to time are always zero and the server can avoid the overhead of requesting the time from the operating system. To turn on statistics, set the value to TRUE. Normally, TIMED_STATISTICS should be FALSE. "
(From the Metalink site, in the Oracle document on ultbstat/utlestat
"Setting TIMED_STATISTICS to TRUE adds only a very small overhead to database operations - it is advisable to keep this set at all times"
Any views ???
Cheers
C
--
"Some days you're the pigeon, and some days you're the statue." Received on Wed Sep 15 1999 - 05:34:20 CDT
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