Some questions.
How many disks?
What model/type of disks?
What model disk controller?
Is anything journaled?
How much memory? (you might have a lot of paging going on)
Do you have any perf tools available to review disks and memory?
Paul
-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Kok.Gregory@xxxxxxxxxxxxxx
Sent: Friday, May 20, 2016 7:36 AM
To: midrange-l@xxxxxxxxxxxx
Subject: Logical Files (Views) - Impact on Performance (I/O)
Hello Midrangers.
We recently implemented a new system on our IBM i720 (v6r1m0). Performance is since negatively impacted and the bottle-neck is massively I/O related.
Disks are not keeping up.
Looking at the size of the systems database, it is 53% Logical Files (Views).
All these views (LF's) were created (CRTLF) with the attribute FILETYPE = DATA. (Most LF's reference a single Physical File only, not multiple PF's) These LF's are occupying physical space on disk (53%... more than half the actual database) and I'm concerned there is an I/O impact because of this ?
Can someone elaborate on what the FILETYPE = DATA setting does ? Is it duplicating physical file data and possibly the source of severe I/O activity ? (Whats the difference between data records and source records
?) Is there any best practice / recommendations re the use of LF's ?
CRTLF (Command - Create Logical File)
Attribute : File type (FILETYPE)
Specifies whether each member of the logical file being created contains data records, or contains source records for a program or another file.
*DATA
The logical file contains data records.
*SRC
The logical file contains source records. This value cannot be specified for join logical files.
Thanks,
G
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