How To
Summary
DFSMSdss is providing a volume compression tool that can assist in determining whether volumes can benefit from compression services.
This tool is a simple application that invokes DFSMSdss full volume dump. The tool will use zEDC services to compress each track that is presented while it keeps a running average of the size of the presented tracks as well as the size of the resulting tracks after compression. Once the Dump full operation is completed successfully, the tool will surface a message that provides volume statistics and a message that provides compression savings summary.
*Any use of this tool should be translated as a ‘Yes/No’ to determine if compression services would be beneficial for a given volume. The compression savings are determined by a calculation of the resulting averages. DFSMSdss makes no promises that actual compression attempts will match the compression savings determined by the tool. Actual results compressing the volume data may vary widely due to many factors that are considered outside of the scope of this tool.
Environment
The following utility control statements are required:
|
Statement |
Use |
|
JOB |
Initiates your job |
|
EXEC |
Specifies the program name (PGM=ADRVCMPT) |
|
SYSPRINT DD |
Defines a sequential message data set. The data set can be written to a system output device, a tape volume, or a direct-access device. |
|
SAMPLEDD DD |
Defines the input (also called the source) volume. |
|
output DD |
Defines the output. The ddname, output, should be defined as a DUMMY DD. |
|
SYSIN DD |
Defines a command data set containing a DFSMSdss command. It usually resides in the input stream, however, it can be defined as a blocked or unblocked sequential data set or as a member of a partitioned data set. Records must be fixed format, LRECL=80 The SYSIN should describe a DFSMSdss DUMP FULL operation. |
|
PARM statement |
The EXEC statement should contain a PARM field with the following: ‘ACTION=16KZEDC’ – Indicates that the tool should use zEnterprize Data Compression services in 16K block increments. |
If the above control statements are not as described – unexpected behavior may occur if not otherwise captured and identified via an error message.
Additional Information
//VCMPTTST JOB ,MSGLEVEL=(1,1),TIME=(5,0),REGION=4096K,
// MSGCLASS=A,CLASS=A
//STEPS01 EXEC PGM=ADRVCMPT,PARM='ACTION=16KZEDC’
//SYSPRINT DD SYSOUT=*
//SAMPLEDD DD UNIT=SYSDA,VOL=SER=myvolser,DISP=SHR
//OUTPUTDD DD DUMMY
//SYSIN DD *
DUMP FULL INDD(SAMPLEDD) -
OUTDDNAME(OUTPUTDD) ADMIN OPTIMIZE(4)
/*
Note:
Volume statistics and compression results are available as CSV output. To obtain such output the following PARM statement should be added:
‘OPTION=CSVOUT'
The resulting CSV output is in the following format:
ADR208I: volFreeCyls(4),EAVtrkFreeCyls(4),VolFreeTrks(4),volFreeExts(4),VolTrkFreeExts(4),VolPercentFree(1)
Eav field is zero on a non-EAV.
ADR584I: ucbDevNo(2),AvgInputTrkSize(4),AvgOutputTrkSize(4),CompressblockSize(4),CompressSavingsPct(1)
(n) = bytes represented. Each byte is two character string.
Sample Results:
DUMP FULL -
INDD(SAMPLEDD) -
OUTDDNAME(OUTPUTDD) ADMIN OPTIMIZE(4)
ADR101I (R/I)-RI01 (01), TASKID 001 HAS BEEN ASSIGNED TO COMMAND 'DUMP '
ADR109I (R/I)-RI01 (01), 2024.180 11:47:40 INITIAL SCAN OF USER CONTROL STATEMENTS COMPLETED
ADR050I (001)-PRIME(01), DFSMSDSS INVOKED VIA APPLICATION INTERFACE
ADR016I (001)-PRIME(01), RACF LOGGING OPTION IN EFFECT FOR THIS TASK
ADR006I (001)-STEND(01), 2024.180 11:47:40 EXECUTION BEGINS
ADR006I (001)-STEND(02), 2024.180 11:47:47 EXECUTION ENDS
ADR208I (VCM)-VCUIM(01), 2024.180 11:47:47 BEGINNING STATISTICS ON C9SS01:
FREE CYLINDERS 00000000
FREE TRACKS 00000012
FREE EXTENTS 00000001
LARGEST FREE EXTENT (CYL,TRK) 00000000,12
PERCENT FREE SPACE 00
00000000,00000000,00000012,00000001,00000000,00
ADR584I (VCM)-VCUIM(01), THE COMPRESSION TOOL RESULTS ARE AS FOLLOWS:
UCB DEVICE NUMBER: 0F40
AVERAGE INPUT TRACK DATA LENGTH: 00055334
AVERAGE OUTPUT TRACK DATA LENGTH: 00003516
PROCESSED BLOCK LENGTH: 16K
COMPRESSION SAVINGS PERCENTAGE: 93
0F40,00055334,00003516,00016384,93
ADR013I (001)-CLTSK(01), 2024.180 11:47:47 TASK COMPLETED WITH RETURN CODE 0000
ADR012I (SCH)-DSSU (01), 2024.180 11:47:47 DFSMSDSS PROCESSING COMPLETE. HIGHEST RETURN CODE IS 0000
Document Location
Worldwide
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Document Information
Modified date:
03 July 2024
UID
ibm17159368