From: James Jackson (James.Jackson@MAIL.STATE.AR.US)
Date: Thu Mar 27 2003 - 11:03:02 EST
For some reason, IBM went through several hoops to provide us with an
e-fix to add the dio mount option for 5.1-JFS2. I don't recall the
specific timing, but we were working with p690's, which of course
require 5.1, and I don't think 4.3.3 ML10 was available yet. But this
was well over a year ago, and my memory has already grown fuzzy.
The reason you describe is precisely why we chose to use the dio mount
option, since Oracle hadn't implement O_DIRECT in the AIX distro. Dio
was identified as a means to avoid the VMM becoming a bottleneck for a
datawarehousing app.
-----Original Message-----
From: Holger.VanKoll@SWISSCOM.COM [mailto:Holger.VanKoll@SWISSCOM.COM]
Sent: Thursday, March 27, 2003 4:56 AM
To: aix-l@Princeton.EDU
Subject: Re: AIX 5.1 / 64-bit Kernel / No JFS2
Unfortunately, we were driven to our 32-bit/JFS2 decision due to the
availability of Oracle 8i for 64-bit as well as our desire to have some
of the performance enhancements introduced by JFS2, namely a direct-I/O
mount option.
in aix 4.3.3 (I think ML10) there is a unsupported/undocumented
mount -o=dio
option
I am not sure if we are talking about the same, so here is what it does:
if files are accessed on this filesystem, their data isnt buffered in
the aix-filecache.
useful if you know that those files arent read again soon and you cant
tell your application to use O_DIRECT
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