ADSM-L

Re: Tape Questions - 3575 Library

1998-07-14 23:40:28
Subject: Re: Tape Questions - 3575 Library
From: Jennifer Davis <jedavis AT DFW DOT NET>
Date: Tue, 14 Jul 1998 22:40:28 -0500
Debbie,

See notes added below to your questions.

Jenn



At 01:04 PM 7/14/98 -0400, you wrote:
>ADSM/AIX 3.1.1.2, AIX 4.2.1, 3575 Library
>
>Does anyone know why ADSM will dismount idle tapes (in a 3575 tape
>library) for some processes, but not for others?  It seems if a DB
>backup, migration, or a restore needs a drive it will dismount an idle
>volume.  Yet if I need to check in a volume to satisfy a mount request
>for reclaim, restore, etc.

[ THERE ARER "PREEMPTION" RULES THAT ADSM FOLLOWS FOR PROCESSES.]
[ADSM DB BACKUPS ARE THE HIGHEST PRIORTY. THIS MAKES SENSE BECAUSE YOU]
["HAVE" TO RUN A BACKUP TO KEEP YOUR RECOVERY LOG FROM FILLING UP - IF THAT]
[HAPPENS, NOTHING ELSE WILL RUN.
[ NEXT, FOR MIGRATION, AGAIN IF YOU RUNS BACKUPS TO DISK AND THE DISK CANNOT]
[MIGRATE, FILLLING UP, BACKUPS STOP. KIND OF WOULD DEFEAT HAVING A BACKUP
TOOL]
[EH? RESTORES, ON THE OTEHR HAND ARE MORE IMPORTANT THAT BACKUPS BECAUSE ]
[OBVIOUSLY YOU NEED TO GET DATA FOR RECOVERY MORE THAN YOU NEED TO BACKUP]
[DATA THAT YOU ALREADY HAVE. OK, NOW THAT YOU'VE GOT THE PICTURE, SUPPORT]
[SHOULD BE ABLE TO PROVIDE YOU MORE DETAILED INFORMATION ON THE EXACT ]
[PRIORITY OF PROCESSES.]



there has to be a drive empty for the task or
>it will fail.  Then I manually (via dismount volume command) dismount
>the volume, and have to run the checkin again.
>
>Also, while we are on the subject of tapes, if ADSM tries to mount a
>tape that has been checked in as scratch, and for some reason the tape
>volume cannot be written to (like maybe an operator checked it in with
>write protect on), why does it continue to attempt the mount of that
>same tape over and over again.

[I BELIEVE THERE IS A FEW APARS ON THIS. I WOULD CALL SUPPORT AND LET]
[THEM CHECK THEM AGAINST YOUR SITUATION]


Processes fail even though there are
>other scratch volumes in the library.  So I guess the question would be
>

>1) How does ADSM select a scratch tape from the library?

[I CAN'T REMEMBER EXACTLY THE ORDER, BUT IF YOU LOOK IN YOU ADSM
ADMINSTRATOR'S]
[GUIDE (I BELIEVE IN THE INDEX UNDER VOLUMES, SEQUENTIAL) IT DETAILS
EXACTLY] [WHAT ORDER ADSM USES TO CALL A TAPE IN A VARIETY OF SCENARIOS]

>2) Why does it give a very deceiving error message "unable to open
>drive".

[I WOULD BE INTERESTED TO SEE THIS ERROR AND THE ERRORS JUST BEFORE AND
AFTER] [IT. (OR CALL SUPPORT) THIS TYPE OF ERROR COMES FROM THE OPERATING
SYSTEM TO] [ADSM. YOU MAY HAVE A NON-ADSM ISSUE THAT NEEDS ATTENTION AND IT
IS "AFFECTING"] [ADSM]
>
>And lastly, ADSM is very smart in some respects, but when it comes to
>tapes it seems the right hand doesn't know what the left is doing.  When
>checking in a tape to satisfy a mount request, why does ADSM have to
>mount the tape, verify the label, put the tape away, then mount the tape
>again for use? (answer for this is probably "because that's how it
>works")

[WELL I DO NOT DENY THAT THERE COULD BE IMPROVEMENTS. HOWEVER, WHEN IT COMES]
[ TO TAPES, ADSM IS ONLY AS SMART AS THE HARDWARE THAT IT IS INTERACTING WITH]
[A "FILET MIGON" LIBRARY IN MANY CASES IS A LOT NICER THAT THE "TOP ROUND" ]
[LIBRARY. THE POINT BEING, THE MORE SOPHISTICATED LIBRARIES THAT HAVE THEIR
OWN]
["Operating System" CONTROLLER WORK NICER, LIKE THE 3494 OR SOME OF THE STK]
[SILOS USING ACSLS]


>Debbie Weeks
>University of South Florida
>Information Technologies/Technical Support
>*********
>*Debbie AT admin.usf DOT edu
>*(813) 974-6926   *  S/C 574-6926
>Fax(813) 974-3054
>
>
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