rbs AT bu DOT edu wrote:
>
> From: rbs AT BU DOT EDU
> To: ADSM-L AT VM.MARIST DOT EDU
> Date: Wed, 16 May 2001 10:50:18 -0400
> Subject: Re: Bizarre tape behavior.
>
> Alan - Looks like your multi-process storage pool backup encountered a file
>        that spanned volumes.  The TSM server code might do better in
> scheduling the sequence of tape mounts to try to avoid such a conflict;
> but timing over the long period that such backups take can thwart schemes
> to deal with the situation, particularly as other events intervene (delays
> due to tape drive availability problems, a higher-priority task taking
> drives, etc.).

Hmmm... yes. The obvious answer would be to have *SM check to see if a
tape is already mounted before trying to mount it a second time! The
first time I encountered this I put my foot in my mouth. I saw "Waiting
for volume 636 seconds" and went to ask the operator why. I have to
multi-thread the tape pool copies. Unfortunately, we are still on 3490
technology here and sooo many tapes are in use and so many mounts are
required that there isn't enough time in the window otherwise. It
bothers me that so much time is wasted when this occurs especially since
I have to be so concerned about fitting the backup into the time
allotted.

>
> What would help would be a new server option, SPANVOLUMES, which we could
> set No to prevent the complications that come with multi-process tasks,
> where we'd be willing to live with the additional time to abandon the
> incomplete file written at the end of a volume to start writing it afresh
> on a new volume.
>
>   Richard Sims, BU

It almost doesn't seem worth it. The real fix would be as I've stated
above. Also, it would make matters much worse for the number of tapes in
use problem. I'm at 8,300 tapes and growing at over 100 per week. It
would be so much nicer if we had a more modern tape technology here. (:

--
Alan Davenport
Alan Davenport
Senior Storage Administrator
Selective Insurance
Alan.Davenport AT selective DOT com
973-948-1306

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