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Conference cookie::aim$notes:disk_defrag

Title:Disk File Optimizer (DFO) for OpenVMS
Notice:Kits and documents: last reply to note 1
Moderator:COOKIE::AMEND
Created:Tue May 16 1989
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:539
Total number of notes:2544

531.0. "why does DFO unshelve files with DEFRAG SHOW ?!" by ATZIS1::KARTNER_M (HOUSTON, we have a problem) Thu Apr 17 1997 05:03

    Hi!
    
    A customer is experiancing an unexpected behaviour with DFO on
    disks with HSM shelved files if these are veri fragmentet.
    
    When the scheduled script is started, that executes a prolog
    that contains a "DEFRAG SHOW DFG$DISK/VOL" files that are
    shelved get UNSHELVED.
    
    This uncovers 2 questions:
    
    	1) why and how does DFO touch the body of a file during a
    	   DEFRAG SHOW DFG$DISK/VOL. Files are unshelved only if
    	   you acces the body of the file. The retreival pointers
    	   are located in the fileheader
    
    	2) how is the process tree of the DFO built up?
    	   If you enter the DEFRAG SHOW DFG$DISK/VOL interactive from
    	   a process that is set to SET PROCESS /NOAUTOUNSHELVE
    	   everything works fine.
    	   The customer has entered a SET PROCESS /NOAUTOUNSHELVE at the
    	   begin of the PROLOG file. But there seems to be some subprocess
    	   of DFO that is set to SET PROCESS /AUTOUNSHELVE
    
    	   The defaultbehaviour of DFO should be changed to not touching
           SHELVED files in any case !!
    
    
    	Thanks in advance
    	Michael
    
    Following infos to the SCRIPT:
    
    $ DEFRAG SHOW DUA6_L2
    Disk File Optimizer for OpenVMS DFG V2.2
    � 1996, Digital Equipment Corporation
    
    Volume script DUA6_L2 is ENABLED, LEVEL=2, device: $1$DUA6
    No defragmentation process is executing
    Scheduler queue contains the following operations:
        DEFRAGMENT VOLUME $1$DUA6 on 18-APR-1997 02:00:00.00
    Consolidate freespace
    Script repeat interval: 1 00:00:00.00
    Defragmentation time limit 0 03:30:00.00
    Minimum Priority: 1
    Default Priority: 2
    Script may operate on the following nodes:
        MARS
        VENUS
    Log file: RZ:[DEFRAG]DUA6_L2.LOG;/BRIEF
    Prologue file:  RZ:[DEFRAG]SHOW.COM;
    Epilog file: RZ:[DEFRAG]SHOW.COM;
    Mail notification is OFF
    OPCOM notification is ON
    Special file handling:
        Files specified in options file: RZ:[DEFRAG]DUA6.OPT;
    
    Prolog-File
    
    $ TY RZ:[DEFRAG]SHOW.COM;
    $ SET PROCESS/NOAUTO_UNSHELVE
    $ SET PROCESS/NOAUTO_UNSHELVE/IDENT='F$GETJPI (0, "MASTER_PID")'
    $ DEFRAG SHOW DFG$DISK/VOL
T.RTitleUserPersonal
Name		DateLines
531.1Which HSM product is the customer usingCOOKIE::AMENDFri Apr 18 1997 09:2332
Michael

  Which HSM product is the customer using?  Is it Digitals or
  another vendors?  I have heard that other vendors HSM has this
  problem.  I do a show all the time on disk that have Digitals
  HSM on them and I never set NOUNSHELVE and it does not unshelve
  them.

  If you do not do the SHOW, does the files get unshelved?
  
  The command procedure has nothing to do with the
  defragmentation process, the command proceedure is a subprocess
  of the defragmentation process.
  
>    A customer is experiancing an unexpected behaviour with DFO on
>    disks with HSM shelved files if these are veri fragmentet.

  I do not understand how a file that is shelved can be
  fragmented or is the volume very fragmented?

  The problem that you see with SET PROCESS /NOAUTOUNSHELVE not
  working in the command procedure could be caused by the privs
  that you have at that time.  Doing it interactively, you can
  turn on all the privs.  However, the command procedures only
  have BYPASS, CMKRNL, DETACH, EXQUOTA
  , NETMBX, SHARE, SYSGBL, SYSLCK, SYSPRV, TMPMBX, and WORLD

  I will try this on our system that is running Digitals HSM
  product.
  
  thanks
    jim amend
531.2More questionsCOOKIE::AMENDFri Apr 18 1997 15:2429
Michael

  I started looking at the problem and I cannot reproduce the
  problem here so I have to get some help from the HSM people to
  try and recreate the scenario.  They cannot help me until
  Monday.  I just want to make sure that I can answer questions
  the HSM people ask me and I can recreate the scenario you have.

  If you execute the DUA6_L2 script with no prologue and epilogue
  file, does the defragmentor unshelve the files?  I want to know
  if it is only happening with the show command in a prologue or
  epilogue file or does the defragmentor process cause the files
  to be unshelved.  That way I can look at what they do not have
  in common.

  If you do an interactive SHOW command and SET
  PROCESS/AUTOUNSHELVE does this unshelve files?
  In your message you only say you SET PROCESS/NOAUTOUNSHELVE.  I
  have tried both ways and the SHOW command does not unshelve the  
  files on my disk.  However, the disk I did it on was not very fragmented.

  Could I get a /full log file of the run of DUA6_L2 script?

  Does this unshelving only happen on disks that are very
  fragmented?

  Thanks
    jim amend
531.3check HSM$LOG:HSM$SHP_AUDIT.LOGCOOKIE::HOLSINGERHSM Engineering, DTN 522-2843Mon Apr 21 1997 10:448
Hello Michael. 

HSM logs each request, including file faults in HSM$LOG:HSM$SHP_AUDIT.LOG. 
Look in the log for the files which were unexpectedly unshelved and you can 
verify the requesting PID and process name. 

Hope this helps, 
/Paul
531.4DFO should not unshelve filesCOOKIE::AMENDMon Apr 21 1997 12:2910
Michael

  During a SHOW command DFO does not touch the body of the file. 
  It only goes through INDEXF.SYS and gets the information.  I
  have tried to recreate the problem here and cannot.  Since you
  have closed the problem with the customer, I will not spend any
  more time on the problem.

  thanks
    jim amend