BackBox H4.00 User Manual

Product Description
16 BackBox H4.00 User Manual
by the VTC to the Domain Manager to register the volume statistics and new idle
state.
Automatic unload occurs when the MEDIACOM REJECT command is issued, or the
tape application is canceled before the load completes.
Automatic unload is also initiated by the daily cleanup (BB017_FREE_EXPIRED
macro) if the volume was abnormally left in LOAD state after its use by the NSK tape
system.
At last resort, an automatic unload is triggered when an unused loaded volume or
device is requested by a new mount request. Several conditions must be satisfied to
take action:
The drive where the volume was loaded is FREE (unused) according MEDIACOM,
And
o The application process that requested the load is not running
anymore,
or
o A new application has requested the same volume and the
media has been mounted for a longer time than the Volume
Group parameter “Automatic unload timeout” value. This
timeout is forced to 24 hours if the original tape application
process is unknown for any reason, e.g. if the load was not
associated with an $ZSVR mount request.
If the volume was pre-loaded as part of a backup set being restored:
• The timeout is computed starting at the unload of the previous
volume.
• If the load of the volume has completed (restore script finished), the
timeout value is the value configured in Volume Group, else the
timeout is 24 hours
Virtual volume storage
Virtual volumes can be stored on a variety of storage, see the different types of Data
Store below: “Windows Data Store”, “TSM Data Store”.
In all types of Data Stores, the size of the storage space allocated to a virtual volume
is equal to the size of data actually written, plus a marginal amount of metadata,
regardless of the maximum size specified in the Volume Group.
The image of each virtual volume is kept indefinitely in the Data Store until:
The virtual volume is rewritten by the Guardian tape application, or
The BB017_FREE_EXPIRED batch TACL macro frees the storage of volumes
declared expired by DSM/TC and TMF, or
The virtual volume is deleted manually through the Web user interface.