FUJITSU CentricStor V3.1D - Manual (Page 76)

76 U41117-J-Z125-7-76
Reorganization Selected system administrator activities
Once the number of scratch tapes reaches the hard limit again, the “all clear” is given
(see
page 76 ):
SXPL011 ... PLM(#11): NOTICE: number of free PVs of PV-group <PVG> over
absolute minimum (<num>) again
For the following statuses, reorganization is only initiated within the configured time of day
interval. When several of these statuses exist simultaneously, the PLM prioritizes the reor-
ganization of the physical volumes affected in the specified order.
● Physical volumes which have reached refreshing age
Once the data on physical volumes exceeds a certain age, the physical volumes are
reorganized in accordance with the settings in the physical volume group (see
section
“Physical Volume Groups” on page 187 ). In the process, the logical volumes are written
anew to another physical volume.
● Physical volumes in the faulty or inaccessible status
● Soft minimum status
This status exists when the number of scratch tapes has fallen below the configured soft
minimum
and at the same time read tapes exist whose occupancy level is below the con-
figured percentage value (Fill Grade parameter).
When the hard minimum is fallen below and at the same time physical volumes in faulty or
inaccessible
status or which have reached the refreshing age exist, these physcial volumes
are not taken into account for reorganization. When this situation occurs, highest priority is
assigned to the most effective method of obtaining new scratch tapes: physical volumes in
faulty
or inaccessible status cannot be reused anyway, and those which have reached the
refreshing age normally have a high occupancy level and can easily cope with a delay of a
few hours which is slight in comparison to their age.
4.4.4 Which physical volume is selected for reorganization?
Selection of a physical volume for reorganization takes place randomly in the following
groups and does not depend on its occupancy level:
● Physical volumes selected by means of an explicit command
● Physical volumes which have reached the refreshing age
● Physical volumes in faulty or inaccessible status
Further physical volumes are queued for reorganization only if the first limit value for the
number of scratch tapes (soft minimum) is fallen below. In the group affected in this case, the
next physical volume selected is the one for which the lowest costs for copying the logical
volumes are estimated.