Fujitsu Siemens Computers pmn User Manual page 77

Selected system administrator activities
Only physical volumes in read status on which the relative proportion of valid data is less
than the percentage value configured in the Fill Grade parameter are taken into account. If
a physical volume is in write status and the percentage value for its valid data drops below
the Fill Grade value, it is placed in read status and is therefore a candidate for reorganization.
The costs are estimated according to the following formula:
( N * estimate1 ) + ( M / estimate2 )
where
N
estimate1
M
estimate2
When the two estimated values are configured, it must be borne in mind that these do not
depend solely on the hardware characteristics of the tape drives, but also to a large degree
on the relative size of the valid logical volumes. For example, large logical volumes have
fairly certainly been displaced from the TVC and would have to be read in first, which practi-
cally doubles the time required and halves the write performance.
Example
pos PV
:
15 CSJ016 JAGUAR JAG001 _r__
16 CSJ017 JAGUAR JAG001 _r__
:
The default values (Write Overhead = 3, Write Throughput = 5) result in the following costs:
PV
CSJ016
CSJ017
CSJ016 is therefore selected.
Example with Write Overhead = 3 and Write Throughput = 20:
PV
CSJ016
CSJ017
CSJ017 is therefore selected.
U41117-J-Z125-7-76
Number of valid logical volumes on the physical volume
Estimated overhead, in seconds, for each logical volume which is to be writ-
ten (configuration parameter Write Overhead)
Sum, in MiB, of the data contained on the valid logical volumes
Estimated write performance in MiB/sec (configuration parameter Write
Throughput)
TL PVG state
Number of valid LVs
583
1
Number of valid LVs
583
1
next-bl LVs - val
2518971 1156 583 279.397
1109297 16
Valid data volume (MiB)
0
16155
Valid data volume (MiB)
0
16155
Reorganization
cap/GB valid/GB
0.000
1 279.397 15.795
Estimated costs
1749
3234
Estimated costs
1749
810
valid %
0
5
77