HP OpenVMS Systems

MOUNT/BIND, Bound Volumes, and Disk Performance?

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The Question is:

 
This will be a two-part question about bound VMS disk-sets.
 
1) After a set of disk have been initialized and bound together by using the
 command "MOUNT/SYSTEM/BIND=BLD_TEST DKA0:,DKA100: BLD_TEST_1, BLD_TEST2
 BLD_TEST".  I then wanted to change the disk labels by using the commands:
 "SET VOLUME/LABEL=BLD_DSK_1 DKA
0:" and "SET VOLUME/LABEL=BLD_DSK_2 DKA100:", this worked as expected and
 change the disk volume names.
 
The problem occurs when I want to mount the disk back to the system.  By using
 the command "MOUNT/SYSTEM/BIND=BLD_DSK DKA0:,DKA100: BLD_DSK_1,BLD_DSK_2
 BLD_DSK", I get the fatal error message of: "%MOUNT-F-VOLINSET, volume is
 already part of another volum
e set".  I have to use the original name of "BLD_TEST" with the /bind command.
 
How can I change the name given to the "/BIND" command to something different?
 
 
2) I ran a benchmark job on a set of newly created bound VMS disk-set and
 received a wall time of 1-hour and 10-minutes.
 
After coping all additional information that is also need on this bound
 disk-set and I ran the same benchmark job with the same environment, the wall
 time had increased to about 1-hour and 40-minutes.  This is an increase of 30
 minutes.
 
The disk that I'm using are "SEAGATE ST336704LC" 35 gb drives in a two-bay
 Phoenix PDS100-S2W-2RDR housing.
 
Why am I getting an increase in my benchmark times?
 

The Answer is :

 
  The OpenVMS Wizard generally discourages the current and continued
  use of bound-volume sets, and would strongly discourage new uses.
 
  The bound-volume set mechanism is an outdated solution to a problem
  of insufficient volume capacity, and has various significant drawbacks
  in terms of usage, volume management and general operations.
 
  Just one of the possible problems is erratic I/O performance, as the
  actual behaviour of a sequence of I/O operations is highly dependent
  on the precise state of the members.  The OpenVMS Wizard suspects your
  benchmark numbers are illustrating this particular side-effect, though
  the behaviour could obviously have another trigger.
 
  If you need to combine multiple spindles into a single volume, please
  use volume striping (RAID Software for OpenVMS, or other similar
  package), or controller-based RAID, or -- far and away the best and
  simplest solution -- acquire and configure a larger disk.  Again,
  the OpenVMS Wizard would not tend to use MOUNT/BIND and the resulting
  bound-volume set.
 
  Bound volume sets are not supported as OpenVMS system disks.
 
  For assistance with the performance characteristics and the general
  operation of third-party storage, please contact the vendor(s)
  supporting the device(s).  Related information is available in the
  OpenVMS Frequently Asked Questions (FAQ), in the section discussing
  third-party peripheral devices.
 

  

     

     
answer written or last revised on ( 23-JAN-2004 )
     
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