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RE: JFS2 and Concurrent I/O

From: Luis Fernando Cerri <>
Date: Tue, 31 May 2005 14:51:20 -0300
Message-ID: <>

Hello, all.

In my last job, I set up a test environment to check the benefits of = CIO and
JFS2 using:

Oracle 9iR2 ( on AIX 5.2 ML5
Machine: one partition with one processor of an IBM Regatta P690 File-systems: mounted on EMC disks (I don't remember the model)

Once I was the unique user in this machine (test box), the test = consisted of
measure the time took to full import from a dump file, which ended up = in
+15GB of segments (tables, indexes, table partitions). Why I = considerate the
import a good way to measure the benefits? Because during an import we = have
data load and a lot of selects during index creation.

So, I repeated the import 5 times for each of the 4 distinct = configurations,

Db parameter filesystem_io_options: setall or async File-system mounted with or without CIO=20

Between each test, the machine was rebooted to completely clean any = cache
and whatever...

But based on the times I got, I couldn't figure out any conclusion!!!

For example:

CIO enabled and fs_io_opt as setall:=20

1st time: 15 min
2nd time: 16 min
3rd time: 29 min
4th time: 19 min
5th time: 25 min

The times took by the import in any configuration ranged from 15 to 30 minutes, independent on the configuration.

What are your comments? Did I build a good test environment using = import?
Could you guess the explanation for the import range from 15 to 30 min = in
the SAME configuration of file-systems, db params? Remember I were = alone in
the box...

Thanks in advance for your comments.

Best regards,
Luis Cerri

-----Original Message-----
From: =
On Behalf Of Wolfgang Breitling
Sent: ter=E7a-feira, 31 de maio de 2005 14:00 To:
Cc: Oracle-l
Subject: Re: JFS2 and Concurrent I/O

I am using it. Not in production yet. Any specific questions?

Peter Barnett wrote:
> Is anyone using this? If so, what is your experience?


> Thanks,



Wolfgang Breitling
Centrex Consulting Corporation

Received on Tue May 31 2005 - 13:56:34 CDT

Original text of this message