I was indeed the TSM caching that was causing the slow migration speeds.
I turned caching off on Thursday, and by Friday  I was seeing the high
speeds previously encountered.
Caching had been discounted as a cause as I was running for almost two
weeks with it activated, before the problem arose.
I have not yet made any of the other changes recommended, as I wanted to
track each tweak individually.
It looks like we've hit the bullseye with this one.  The only downside is
that restores will take longer, but I can live with that.


Thanks for the help.

Jim




David E Ehresman <deehre01 AT LOUISVILLE DOT EDU>@VM.MARIST.EDU> on 17/08/2005
13:09:41

Please respond to "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>

Sent by:    "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>


To:    ADSM-L AT VM.MARIST DOT EDU
cc:

Subject:    Re: [ADSM-L] Migration Speed Has Plummeted


>We back up around  220 Gb of data to the disk pool overnight, then migrate
>(with caching on) to cartridge in the morning.
>

I assume you mean TSM storage pool caching rather than 3390 caching.  If
so, I'd turn off caching for a day and see if that makes a difference.  It
is my understanding that TSM caching, while optimizing restore times, can
cause performance problems in other TSM areas.

 David






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