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Re: Oracle Performance Questions

From: Matthias Hoys <anti_at_spam.com>
Date: Thu, 23 Feb 2006 19:43:35 +0100
Message-ID: <43fe0259$0$16371$ba620e4c@news.skynet.be>

<DMina_at_laiki.com> wrote in message
news:1140710855.360626.228910_at_z34g2000cwc.googlegroups.com...
> Hello people,
>
> I have several querstions if somebody can help me. We have ORacle 9i
> Rel 2 installed on AIX 5.2
>
> 1. I have read that JFS and Large File Enabled filesystem is not
> advisable! Do you have any comments on this? My filesystems (all
> datafiles) are Large File Enabled.
>
> 2. If you are using bufferred I/O does it make any sense to have
> multiple buffer caches? (db_16K_cache_size etc) My db_block_size is 8K
>
> 3. If i make use of Direct I/O what changes do i have to change on OS?
> (except of course mounting the filesystem using dio)
>
> 4. Do you use LOCK_SGA=TRUE and if yes what do i have to have in mind
> in terms of OS configuration parameters?
>
> Thank you.
>

  1. Correct. Do NOT use the old JFS filesysyem (except maybe for AIX itself) but use JFS2 for Oracle datafiles.
  2. If you are using filesystems, the optimal configuration is to use 4K block size, on 4K filesystems mounted as CIO (concurrent I/O). This bypasses the AIX buffer cache. For redo log files, you should use filesystems with 512 bytes block size.
  3. Use CIO if possible, and make sure your filesystems have the same block size as your database (recommended : 4K).
  4. I have always used it when creating databases on AIX, since it's mentioned in the installation guide.

HTH
Matthias Hoys Received on Thu Feb 23 2006 - 12:43:35 CST

Original text of this message

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