Re: Large pages

From: <>
Date: Tue, 20 Nov 2012 03:01:43 -0800 (PST)
Message-ID: <>

Tirsdag den 20. november 2012 05.53.47 UTC+1 skrev Noons:
> On Nov 15, 4:05 am, joel garry <> wrote:
> >
> > Don't apologize; blog!  There is surely a shortage of excellent Oracle
> > AIX exposition.
> On a totally different note, nothing to do with Jonathan's point
> whatsoever:
> ...and a lot of plain, DEAD WRONG lore in the so-called "community"
> forums...
> I've lost count of the number of times I've heard "IBM experts" and
> other such claiming in forums that to get performance with Oracle in
> Aix 5L (and later) one needs to mount all jfs2 file systems storing
> database data with the "cio" option.
> Which promptly removes any use of the file system buffer cache for ALL
> Unix commands involving file IO on ANY file in such file systems!
> It could have been true before 10g Oracle.
> Since then, all we have to do is turn on filesystemio_options = SETALL
> and bingo, ALL Oracle data files (and ONLY those) located on jfs2
> filesystems will be opened with the cio option.
> While using the Aix commands on them to copy/move/backup will use the
> normal file system cache and not drop the speed of access.
> But what do I see everywhere I go with Oracle in Aix, regardless of
> what version? All jfs2 file systems mounted with cio option.
> Now, THERE is a "rule of thumb" GUARANTEED to destroy ALL IO
> performance other than through Oracle...
> (groan...)

That's interesting... My reason for requesting the cio mount option for some AIX jfs2 filesystems (which BTW don't contain anything but Oracle .dbf files) is that otherwise any attempt at accessing the .dbf files from "outside" - cp or TSM ARCHIVE - fails with "Invalid argument" because the Oracle instance has the file open with the cio option due to filesystemio_options = SETALL, but the utility attempts to open the file without cio.

My need for this is caused by some .dbf files for a READ ONLY tablespace, which I want to archive on tape, preferably without first taking the tablespace OFFLINE, which is the only workaround I have found. I'm on AIX 5.3. Received on Tue Nov 20 2012 - 12:01:43 CET

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