FYI:

Tuning AIO Servers 
AIX uses asynchronous input/output (AIO) servers to perform asynchronous I/O to 
the disk subsystem. Using AIO can greatly improve SSA performance because the 
server doesn't have to wait for the I/O to complete. For example, to check or 
change your settings: 
root@unxm:/>smitty aio 
Select Change / Show Characteristics of Asynchronous I/O 
The minimum number of servers is the number of AIO servers that get started at 
system boot; the maximum number of servers is the maximum number of servers 
that will run on that machine. When you are starting, your tuning maximum 
should be set to the number of disks performing AIO times 10. Minimum should be 
set to maximum divided by 2. 
To find out how many AIO servers you currently have running, use: 
pstat -a | grep -i aios | wc -l 
If this number equals your minimum value, you may be able to reduce the number 
of AIO servers. If it equals your maximum, you may need to increase the number 
of AIO servers. If it is between your minimum and maximum, no changes should be 
required. 

Miles


----------------------------------------------------------------------------------------------
Miles Purdy 
System Manager
Information Systems Team (IST),
Farm Income Programs Directorate (FIPD),
Agriculture and Agri-Food Canada (AAFC) 
6th Floor 200 Graham Ave.           Mailing: PO box 6100
Winnipeg, MB, CA                                     R3C 4N3
R3C 4L5
Office contact:                                            Mobile contact:
 purdym AT fipd.gc DOT ca                                      purdym AT 
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 ph: (204) 984-1602 fax: (204) 983-7557        Cell: (204) 291-8758

"If you hold a UNIX shell up to your ear, can you hear the C?"
-------------------------------------------------------------------------------------------------

>>> bp3965 AT SBC DOT COM 28-May-04 10:59:11 AM >>>
But what I remember is there is limit for no: of aios  any ideas?

-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Paul Zarnowski
Sent: Friday, May 28, 2004 10:45 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: aix and aio?


It is allowed.  It was recommended to us.  We use it here on our AIX
server.  I can't say whether it helps or not, but it doesn't seem to
hurt.

At 09:10 AM 5/28/2004 -0500, Mike Eggleston wrote:
>Is aio suggested/recommended/allowed on AIX? Is anyone
>using it? Does it help? My current tsm server is AIX
>5.2-ML2, 2GB core, lots of ssa disk (though I've requested
>more to increase the local storage pool to the size of the
>nightly incremental backups), and four fiber connections
>directly to tape drives (3590?).
>
>Mike


--
Paul Zarnowski                         Ph: 607-255-4757
719 Rhodes Hall, Cornell University    Fx: 607-255-8521
Ithaca, NY 14853-3801                  Em: psz1 AT cornell DOT edu