the best performance. It also will try to pick controllers that are currently driving a minimum number of
tapes. So, in an environment with many tape drives per controller, the above algorithm will minimize the
load on any one controller.
The Distance To Drive helps minimize mount times by mounting the tape in a physically close drive. All
other things being equal, the tape will be mounted in the closest drive. However, if the closes t drive is
attached to a heavily used controller, then a more distant drive will be selected.
Retry Mount Time Limit. The default value for this field is -1. When the defa ult value (-1) is used, if an
error is encountered during a PVR mount operation, the mount will pend and be retried ever y 5 minutes.
Setting a value in this field will change the mount behavior to periodically retry the mount until the
specified time limit is exceeded. Once exceeded, an error is generated and the mount request is canceled.
If the mount request would have resulted in a write operation, the error returned will cause the Core
Server to set the VV Condition of the associated tape volume to DOWN. Once in DOWN state, the
volume will no longer be available for read or write operations. For further information about the Core
Server VV Condition, see Section 4.5.4.2: Core Server Tape Volume Information Window on page 271.
Drive Error Limit. This field is used in conjunction with the P VR Server Retry Mount Time Limit. If
the number of consecutive mount errors which occur to any drive in this PVR equal or exceed this value,
the drive is automatically locked by the PVL. The only mount errors that apply are those set through the
Retry Mount Time Limit mechanism. The Drive Error Count field in the PVL Drive Information
records the number of consecutive errors on a drive by drive basis. To turn off the automatic drive
disable feature, set the Drive Error Limit to 0 or -1. Changing its value will not c hange drive disable
behavior until the PVL is recycled.
Serial Number. The serial number of the robot the SCSI PVR is controlling. Used to detect control
paths to the robot.
Dismount Delay. When Defer Dismounts is checked, this value is used by the PVL to deter mine the
number of minutes that dismounts are delayed after the last data access.
Shelf Tape Check-In Retry. The number of seconds the PVR will wait before asking the robot if a
requested shelf tape has been checked-in. The PVR will continue checking at this inter val until the tape is
checked-in. This field applies only if the Support Shelf Tape checkbox is selected. The retry value must
be 30 or greater.
Shelf Tape Check-In Alarm. The PVR will periodically log alarm messages when a requested shel f tape
has not been checked-in. This field specifies the number of minutes between alarms. This fi eld is only
active if the Support Shelf Tape checkbox is selected. The alarm value must be 2 or greater.
Characteristics. Flags for the PVR:
•Defer Dismounts. If ON, the PVL will delay the dismounting of a tape cartridge until the
drive is required by another job or until the Dismount Delay time limit is exceede d.
•Support Shelf Tape. If ON, the PVR and the PVL will support the removal of cartridges
from the tape library using the shelf_tape utility.
•Enforce Home Location. If ON, the SCSI PVR will always try to dismount a mounted cart
back to its home location. Otherwise, it will just use the first free slot. The scsi_home utility
can be used to view and manipulate the home location values.
HPSS Management Guide November 2009
Release 7.3 (Revision 1.0) 142