 |
REORGADON:
An Intelligent & On-Line DFSMShsm (HSM) CDS Reorganization Tool
REORGADON is a tool for
reorganizing IBM's Hierarchical Storage Manager (DFSMShsm) control
data sets (CDS). HSM uses three different control data sets; the
Backup Control Data Set (BCDS), the Migration Control Data Set
(MCDS) and the Offline Control Data Set (OCDS). These control data
sets may be used by HSM in a multi-host environment on single or
multiple systems. REORGADON provides HSM control data set
reorganization while the files are active and online to HSM and
without having to shutdown and restart HSM.
REORGADON reclaims and reorganizes fragmented space in HSM control
data sets. REORGADON allows the selection and processing of a
control data set segment that is "in-use" by HSM on an active single
or multi-system environment.
REORGADON utilizes a number of facilities to ensure control data set
integrity. To facilitate an on-line reorganization, an HSM/R control
address space must be initiated on all connected systems to handle
and synchronize cross system communications. Other component files,
a communications, a log file and a journal file all work together to
ensure update integrity while HSM is active. To reorganize a control
data set segment, a new segment must first be defined. REORGADON
allows the cloning of an existing segment with the exact data set
characteristics. The size of a segment can be changed during its
definition and the segment can also be allocated on a new DASD
volume. After the new segment is defined, all HSM/R address spaces
are directed to manage updates on each system. After the contents of
the original control data set segment and all updates are written to
the new segment, HSM is internally quiesced momentarily while the
old and new segment names are modified. Then control is released and
HSM begins using the new physical segment.
HSM CDS’s are VSAM Key Sequence Data Sets (KSDS). These CDS’s
contain records that describe data set entries that have been
processed by HSM. As records are added to a KSDS, VSAM eventually
generates CI and CA splits. The CI and CA splits fragment space
within the KSDS eventually resulting in an out of space condition.
HSM warns of impending out of space conditions by issuing the WTO
ARC0909E and ARC0911E error messages. These messages indicate that
the current threshold for space has been exceeded. This threshold
can be changed via the SETSYS MONITOR command.
Further information about the CDS’s can be obtained via the QUERY
command with CONTROLDATASETS parameter. Status is reported in the
ARC0148I and ARC0948I messages.
To resolve HSM CDS reorganization issues without REORGADON, IBM
documents:
|
■ |
If the MCDS, BCDS, or OCDS is
full enough to require action, DFSMShsm should be shut down. |
Furthermore, IBM documents, prior
to a DFSMShsm shutdown, there are some options you can use:
|
■ |
Delete old or unneeded
records, such as old statistics records, by using the DELETE
parameter of the FIXCDS or REPORT command. |
|
■ |
Run migration cleanup using
the SETSYS command with the SECONDARYSPMGMTSTART parameter
and the DEFINE command with the SECONDARYSPMGMTCYCLE
parameter. |
Finally, IBM technical
documentation suggests, after DFSMShsm shutdown:
|
■ |
Reclaim fragmented space by
performing an IDCAMS EXPORT and IMPORT of the data set or by
copying the data set out and back using the IDCAMS REPRO
command. If reclaiming fragmented space does not provide
sufficient space, a larger control data set should be
allocated. |
REORGADON eradicates the problems
and restrictions associated with batch HSM control data set
reorganization. REORGADON provides the HSM administrator with an
online option for reorganization of HSM control data sets.
While HSM is active, REORGADON:
|
1. |
Copies the current HSM CDS to
the new CDS. |
|
2. |
Applies all updates to the new
CDS that HSM made while the CDS was being copied and updated
(at this point, all the records in the current CDS and new
CDS are identical). |
|
3. |
Quiesces HSM momentarily on
all systems. The current CDS is renamed (for posterity, the
current CDS is preserved by rename), the new CDS is renamed
to match the original CDS name, and the new CDS is ready to
be used by HSM. |
|
4. |
Releases HSM from its quiesced
state and HSM continues processing using the new CDS which
now has the original CDS name. |
REORGADON maintains full cross
system update integrity while the reorganization of a CDS
segment is performed. Normal HSM processing is not inhibited or
interrupted in any way on any of the connected systems during
the copy process. HSM is quiesced momentarily on all systems
while the current CDS is renamed and the new CDS is put in its
place. Thus the HSM CDS’s are reorganized, on-line, without
impact to Batch Processing or HSM activity associated with
backup, dump, migration, recall, et al…
back to top
Maintaining 24*7 DFSMShsm CDS availability, even when a CDS full
condition occurs. |
|
