Re: Sizing JFSLog

From: Bill Verzal (BVerzal@KOMATSUNA.COM)
Date: Thu Jun 26 2003 - 13:41:41 EDT


I would say that a question like this is very much like "How much swap
space is needed?"

If your filesystems are fairly static, then a single JFSlog will suffice.
If you have high amounts of I/O to filesystems, then more may be in order.
The system error log will tell you if there are JFSlog shortcomings.

I've run DB2 backups to 136 concurrent 2GB mount points with a single
JFSlog and never had any JFSlog problems.

BV
--------------------------------------------------------

Bill Verzal
AIX Administrator, Komatsu America
(847) 970-3726 - direct
(847) 970-4184 - fax

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I am in an AIX performance tunning class as of this writing.
We were told 4 mb for each 2 gig of file system space.

-----Original Message-----
From: "IBM AIX Discussion List" <aix-l@Princeton.EDU> on behalf of
"Theresa Sarver" <tsarver.IFMC@SDPS.ORG>
Sent: Thu, 26 Jun 2003 12:22:12 -0400
To: "aix-l@Princeton.EDU" <aix-l@Princeton.EDU>
Subject: Sizing JFSLog

Hi All;

What is the proper size of the JFSLog on an AIX system (either 433 or 5L)?

I have always set it at the default of 1PP. However, I have a colleague
that is saying that "IBM recommends a 2 MB log size per 1 GB of file system
space."

I can't find any documentation stating that either one is correct...does
anyone know where I might find some?

Thank you!
Theresa



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