Computer Drive User Manual

Score =
Weight 1 * Cartridges from this job mounted on this drive’s controller +
Weight 2 * Cartridges from other jobs mounted on this drive’s controller +
Weight 3 * Units of distance from the cartridge to the drive
This method has the effect of distributing a striped tape mount across as many controllers as possible for
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 best performance will be achieved
by minimizing the load on any one controller.
The Distance To Drive helps minimize mount times by mounting the tape in a physically close drive.
For IBM robots, the time it takes to move a cartridge to a more distant drive is not significant, so the
default value here is fairly low. All other things being equal, the tape will be mounted in the closest
drive. However, if the closest drive is attached to a heavily used controller, then a more distant drive will
be selected.
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 interval 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 shelf tape
has not been checked-in. This field specifies the number of minutes between alarms. This field applies
only if the Support Shelf Tape checkbox is selected. The alarm value must be 2 or greater.
Dismount Delay. When Defer Dismounts is checked, this value is used by the PVL to determine the
number of minutes that dismounts are delayed after the last data access.
Retry Mount Time Limit. The default value for this field is -1. When the default value (-1) is used, if an
error is encountered during a PVR mount operation, the mount will pend and be retried every 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 intended to be used in conjunction with the PVR 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. Since this field is employed by the
PVL, changing its value will not change drive disable behavior until the PVL is recycled.
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 exceeded.
HPSS Management Guide November 2009
Release 7.3 (Revision 1.0) 117