Reorganization Of The Tape Cartridges - Fujitsu Siemens Computers pmn User Manual

CentricStor - Virtual Tape Library

2.5.4 Reorganization of the tape cartridges

When a logical volume is released by the host's volume management facility (e.g. MAREN
in BS2000/OSD), it is flagged accordingly in the CentricStor data maintenance facility which
contains the metadata for each volume. This process, combined with updates (see the
section
data on the real tape cartridges to increase more and more over time (stacked volume with
gaps). If the number of scratch tapes for a CentricStor system falls below a configurable
lower limit, the PLM automatically performs a reorganization by using the VLM to load any
logical volumes still valid into the RAID system and then, so to speak, moving them
piecemeal onto scratch tapes.
CentricStor
VLM
Figure 12: Example of a reorganization
Read tape:
Scratch tape: Tape cartridge that only contains invalid data and has been released for
Write tape:
U41117-J-Z125-7-76
section "Creating a directory" on page
LV0000
LV0003 LV0004 LV0005
LV0009
:
:
LV0037
PLM
TVC
LV0000
LV0003 LV0004 LV0005
LV0009
:
:
LV0037
LV0006 LV0007
Tape cartridge that still contains valid data but has no free space for write
operations
rewriting
Tape cartridge that still contains space for write operations
36), will cause the areas containing invalid
LV0001
LV0010
LV0001
LV0010
LV0001
LV0009
Administering the tape cartridges
LV0002
LV0006 LV0007 LV0008
LV0011
LV0002
LV0006 LV0007 LV0008
LV0011
LV0002
LV0003
LV0011
PV0000
PV0001
PV0002
:
:
PV0007
PV0008
PV0000
PV0001
PV0002
:
:
PV0007
PV0008
37