ADSM-L

Re: [ADSM-L] mediawait during backup to disk

2010-04-30 15:30:35
Subject: Re: [ADSM-L] mediawait during backup to disk
From: "Allen S. Rout" <asr AT UFL DOT EDU>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Fri, 30 Apr 2010 15:26:39 -0400
>> On Fri, 30 Apr 2010 14:07:56 -0400, Keith Arbogast <warbogas AT INDIANA DOT 
>> EDU> said:


> I'll redefine smaller, more plentiful TSM volumes for this pool, and
> see if that keeps the sand out of my socks.

Heh. :) Good luck.

Don't go nuts with the "smaller" direction.  There are major
performance problems at the extremes.


Unless you're running on something radically distributed like an XIV,
you're going to want to keep the underlying spindles in mind.  Every
RAID group constitutes a contention domain.  100 processes trying to
write to the same RAID5 is similar to 100 processes trying to write to
the same spindle.  In fact, they _are_ all trying to write to the same
spindle, times the number of spindles in your group.


If you don't have some other force guiding your decision, I'd suggest
a one-digit number of volumes per contention domain.  Maybe even less
than 5.



- Allen S. Rout