FASTCPK
Overview | Features | Benefits
| Case Studies | Brochures
Modern virtual disk arrays, such as
the IBM ESS Shark, EMC Symmetrix, Hitachi 9900 and the StorageTek
SVA, are still regarded by the OS/390 operating system
as a set of conventional DASD volumes. Each logical volume in the array has
a fixed number of cylinders, and space is managed in the usual way with a
standard VTOC and VTOCIX.
If datasets are over-allocated, then the unused space on the volume is not
available for allocation to other data sets. The total number of extents for
many dataset types is still limited to 16 per volume and if freespace on a
volume becomes fragmented, it can be difficult to allocate new data sets.
With the above considerations in mind, it is clear to see why there is still
a very real need for a product like FASTCPK, with key features
including:
- Freespace Fragmentation--FASTCPK
can consolidate the freespace on a volume into as few as
one or two contiguous
areas.
- Multiple Extent Consolidation--FASTCPK
can merge the extents of Sequential, PDS, PDSE, VSAM, DB2
and Extended Format datasets--eliminating the need
to run DFSMShsm extent consolidation.
- Space Release--FASTCPK
can release all or part of the unused space within Sequential,
PDS, PDSE,
VSAM, DB2 and Extended Format datasets.
- VTOC Manipulation--FASTCPK
can perform a complete analysis of a VTOC, detecting
(and in most cases
fixing) logical errors, such as invalid Format 5 DSCBs
and incorrect freespace definitions. Volumes can be selected
by specific or masked volsers, or by SMS Storage Group
names.
FASTCPK is ultra-fast! Instead of chipping away at a volume over several hours,
you can get the job done in just a few minutes. For example, when run against
a 3390-3 the average run time to consolidate free space, merge extents, and
release unused space is about 2 minutes. If you just want to release
unused space, the TYPE=RLSE mode usually runs in less than 10 seconds!
When used in conjunction with the FDRINSTANT component
of the FDR DASD Management Family, FASTCPK's performance can be further enhanced
by interacting with advanced
DASD subsystem features, such as IBM/StorageTek SnapShot Copy and EMC's TimeFinder.
This example illustrates a standard FASTCPK against
a group of TSO and TEST DASD volumes, identified by the "VOL=" parameter.
The Compaktion will only take place on each volume if the number of freespace
extents exceeds
20, as dictated by the CPKFREEX parameter. The IBM Fragmentation Index can
also be used. PSRLSE, PORLSE and VSRLSE parameters specify that all unused
space will be released from Sequential, PDS, PDSE and VSAM datasets--but only
if they have a secondary allocation coded. (NOSECOND=NORLSE).
//FASTCPK EXEC PGM=FDRCPK,REGION=0M
//SYSPRINT DD SYSOUT=*
//SYSMAP DD SYSOUT=*
//SYSSUMM DD SYSOUT=*
//SYSIN DD *
COMPAKT TYPE=FASTCPK,VOL=(TSO*,TEST*),CPKFREEX=20,
NOSECOND=NORLSE,PSRLSE=ALL,PORLSE=ALL,VSRLSE=ALL
The example below illustrates how FDRINSTANT
allows FASTCPK to interface with SnapShot Copy, via the SNAPSHOT=YES
keyword. Using SnapShot Copy services, FASTCPK can move data
tracks within the DASD Subsystem, significantly
reducing the elapsed time of the job. Typically, an “Instant” Compaktion
against a 3390-3 in an RVA/SVA with SnapShot Copy will run
in less than 10 seconds!
//FASTCPK EXEC PGM=FDRCPK,REGION=0M
//SYSPRINT DD SYSOUT=*
//SYSMAP DD SYSOUT=*
//SYSSUMM DD SYSOUT=*
//SYSIN DD *
COMPAKT TYPE=FASTCPK,STORGRP=PROD,SNAPSHOT=YES
FASTCPK can produce a wide range of
information, in both detailed and summary format. The MAP
function allows you to map out the contents of selected volumes,
while the SIMULATE feature lets you see the effects of a
Compaktion without actually having to run it for real. Before
and After maps can be produced for each volume processed,
either on a SIMULATE or a real Compaktion, together with
a concise summary of the effects of the Compaktion. Here
is an example of the summary report: 
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