IBM Mainframe Forum

by **santlou** » Sat Oct 25, 2008 11:39 am

Using LISTCAT output, How can I determine the DASD utilization of a VSAM file?

When I compare the HI-A-RBA and HI-U-RBA from a LISTCAT to the FileAid Display, I do not get an exact match. What am I missing?

I'm trying to verify the figures on the LISTCAT with the numbers from FileAid.
I understand that LISTCAT isn't always accurate especially if the file is still open. However, for certain cases as the one that I describe here, I would think that it would be accurate.

Take this scenario:

1. I allocate a VSAM KSDS file via FileAid, with a Primary allocation of One (1) Cylinder.

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File-AID --------------- Allocate New VSAM Cluster --------------------------
COMMAND ===>
Component names:
Cluster: 'SAVT.TEST.VSAM'
Data component ===> 'SAVT.TEST.VSAM.DATA'
Index component ===> 'SAVT.TEST.VSAM.INDEX'
Dataset type ===> KSDS (KSDS; ESDS; RRDS; LINEAR)
Owner ID ===> SANTLOU
Specify SMS Class Information:
Storage ===> STD Data ===> VSAM Management ===> V060N370

Space Allocation: DATA Component KSDS INDEX Component (Blank for default)
Volume serial ===> V1XT4G ===> V1XT3C
Units ===> CYLS ===> TRKS (TRKs; CYLs; RECs; K; M)
Primary ===> 1 ===> 1 (Amount in above units)
Secondary ===> 2 ===> 1 (Amount in above units)
Reusable ===> YES (Y = Yes; N = No)
Key length ===> 34 (1-255 - Required for KSDS, opt. RRDS)
Key position ===> 0 (0-max recordsize for KSDS, opt. RRDS)
Average Recordsize ===> 200 (Not allowed for LINEAR)
Maximum Recordsize ===> 200 (Not allowed for LINEAR)
Expiration date ===> (YYYY/MM/DD or blank)
Extended allocate ===> NO (Y = Yes; N = No)

2. Immediately after allocating the file, when I display the VSAM Information in FileAid, it shows that the Allocated Space in indeed 15 Tracks (1 Cylinder on a 3390)

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File-AID ----- VSAM Information - (Page 2 of 3 ) ------- MULTI-VOLUME DATASET
COMMAND ===>
Related Datasets - 'SAVT.TEST.VSAM'
CLUSTER - SAVT.TEST.VSAM Storage: STD
Data: VSAM
Management: V060N370
Owner ID: SANTLOU
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Current Allocations in Tracks: Current Utilization in Tracks:
Allocated space: 15 Used data space: 0 ( 0 %)
Allocated extents: 1 Used extents: 0 ( 0 %)
Allocation type: UNIQUE Prime records:
KSDS Index Allocation in Tracks: Deleted records: 0
Allocated space: 1 Inserted records: 0
Number of records: 0 Updated records: 0
- - - - - - - - - - - Current Reorganization Information - - - - - - - - - - -
Data - Control Area Information: Control Interval Information:
Physical record size: 8192 Size-data: 8192 Index: 1536
Records per track: 6 Number CIs/CA: 90
Tracks per CA: 15 Number free CIs/CA: 0
Retrieved records: 0 Percent free CIs/CA: 0
Max record number 0 Percent free bytes/CI: 0
Number CA splits: 0 Number CI splits: 0

3. However, when I look at the LISTCAT ALL output for this dataset, the Hi-A-RBA is 737280 which is only 13.01 tracks (3390 track size is 56664). Why isn't the Hi-A-RBA 849960 (56664 * 15)? Even the LISTCAT shows the Primary allocation Extent is 15 Tracks. So why wouldn't the HI-A-RBA also reflect 15 tracks instead of 13.01 tracks? Even if I round Up, it's still only result in 14 Tracks.

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CLUSTER ------- SAVT.TEST.VSAM
IN-CAT --- CATALOG.VSAVT01
HISTORY
DATASET-OWNER----SANTLOU CREATION--------2008.299
RELEASE----------------2 EXPIRATION------0000.000
SMSDATA
STORAGECLASS --------STD MANAGEMENTCLASS-V060N370
DATACLASS ----------VSAM LBACKUP ---0000.000.0000
BWO STATUS------00000000 BWO TIMESTAMP---00000 00:00:00.0
BWO---------------(NULL)
RLSDATA
LOG ----------------(NULL) RECOVERY REQUIRED --(NO) FRLOG ------------(NULL)
VSAM QUIESCED -------(NO) RLS IN USE ---------(NO)
LOGSTREAMID-----------------------------(NULL)
RECOVERY TIMESTAMP LOCAL-----X'0000000000000000'
RECOVERY TIMESTAMP GMT-------X'0000000000000000'
PROTECTION-PSWD-----(NULL) RACF----------------(NO)
ASSOCIATIONS
DATA-----SAVT.TEST.VSAM.DATA
INDEX----SAVT.TEST.VSAM.INDEX
DATA ------- SAVT.TEST.VSAM.DATA
IN-CAT --- CATALOG.VSAVT01
HISTORY
DATASET-OWNER-----(NULL) CREATION--------2008.299
RELEASE----------------2 EXPIRATION------0000.000
ACCOUNT-INFO-----------------------------------(NULL)
PROTECTION-PSWD-----(NULL) RACF----------------(NO)
ASSOCIATIONS
CLUSTER--SAVT.TEST.VSAM
ATTRIBUTES
KEYLEN----------------34 AVGLRECL-------------200 BUFSPACE-----------17920 CISIZE--------------8192
RKP--------------------0 MAXLRECL-------------200 EXCPEXIT----------(NULL) CI/CA-----------------90
STRIPE-COUNT-----------1
SHROPTNS(2,3) SPEED UNIQUE NOERASE INDEXED NOWRITECHK NOIMBED NOREPLICAT
UNORDERED REUSE NONSPANNED EXTENDED EXT-ADDR
STATISTICS
REC-TOTAL--------------0 SPLITS-CI--------------0 EXCPS------------------0
REC-DELETED------------0 SPLITS-CA--------------0 EXTENTS----------------1
REC-INSERTED-----------0 FREESPACE-%CI----------0 SYSTEM-TIMESTAMP:
REC-UPDATED------------0 FREESPACE-%CA----------0 X'0000000000000000'
REC-RETRIEVED----------0 FREESPC-----------737280
ALLOCATION
SPACE-TYPE------CYLINDER HI-A-RBA----------737280
SPACE-PRI--------------1 HI-U-RBA---------------0
SPACE-SEC--------------2
VOLUME
VOLSER------------V1XT4F PHYREC-SIZE---------8192 HI-A-RBA----------737280 EXTENT-NUMBER----------1
DEVTYPE------X'3010200F' PHYRECS/TRK------------6 HI-U-RBA---------------0 EXTENT-TYPE--------X'40'
VOLFLAG------------PRIME TRACKS/CA-------------15
EXTENTS:
LOW-CCHH-----X'003A0000' LOW-RBA----------------0 TRACKS----------------15
HIGH-CCHH----X'003A000E' HIGH-RBA----------737279
INDEX ------ SAVT.TEST.VSAM.INDEX
IN-CAT --- CATALOG.VSAVT01
HISTORY
DATASET-OWNER-----(NULL) CREATION--------2008.299
RELEASE----------------2 EXPIRATION------0000.000
PROTECTION-PSWD-----(NULL) RACF----------------(NO)
ASSOCIATIONS
CLUSTER--SAVT.TEST.VSAM
ATTRIBUTES
KEYLEN----------------34 AVGLRECL---------------0 BUFSPACE---------------0 CISIZE--------------1536
RKP--------------------0 MAXLRECL------------1529 EXCPEXIT----------(NULL) CI/CA-----------------25
SHROPTNS(2,3) SPEED UNIQUE NOERASE NOWRITECHK NOIMBED NOREPLICAT UNORDERED
REUSE EXTENDED EXT-ADDR
STATISTICS
REC-TOTAL--------------0 SPLITS-CI--------------0 EXCPS------------------0 INDEX:
REC-DELETED------------0 SPLITS-CA--------------0 EXTENTS----------------1 LEVELS-----------------0
REC-INSERTED-----------0 FREESPACE-%CI----------0 SYSTEM-TIMESTAMP: ENTRIES/SECT-----------9
REC-UPDATED------------0 FREESPACE-%CA----------0 X'0000000000000000' SEQ-SET-RBA------------0
REC-RETRIEVED----------0 FREESPC------------38400 HI-LEVEL-RBA-----------0
ALLOCATION
SPACE-TYPE---------TRACK HI-A-RBA-----------38400
SPACE-PRI--------------1 HI-U-RBA---------------0
SPACE-SEC--------------1
VOLUME
VOLSER------------V1XT3A PHYREC-SIZE---------1536 HI-A-RBA-----------38400 EXTENT-NUMBER----------1
DEVTYPE------X'3010200F' PHYRECS/TRK-----------25 HI-U-RBA---------------0 EXTENT-TYPE--------X'40'
VOLFLAG------------PRIME TRACKS/CA--------------1
EXTENTS:
LOW-CCHH-----X'00170007' LOW-RBA----------------0 TRACKS-----------------1
HIGH-CCHH----X'00170007' HIGH-RBA-----------38399

This is a relatively simple example. So I thought that I could use the HI-A-RBA to show 15 tracks. Is there something else that I should add to the HI-A-RBA to correctly calculate the correct number of allocated tracks? I want to extend this calculation to the HI-U-RBA also.

So basically, I am trying to find the current Allocated Space and the current Space Utilized by a VSAM dataset, using the LISTCAT output. For other files that currently have data in them, the HI-U-RBA reflects the space used. But when I calculate this number, it also does not compare to what FileAid displays.

I would appreciate a push in the right direction. I've checked the IBM manuals on IDCAMS, but basically all I found is that the HI-A-RBA is the number of bytes allocated by the file.

I've attached the LISTCAT output as a file in case it did not format correctly using the "code" container.

Thanks for any assistance

by **dick scherrer** » Tue Oct 28, 2008 10:54 am

Hello,

when I look at the LISTCAT ALL output for this dataset, the Hi-A-RBA is 737280 which is only 13.01 tracks

Yes, this is as it should be.

With a block size of 8192, there are 7512 "lost" bytes per track. 6 blocks of 8192 will fit on one of these tracks which totals 49152 bytes. When you multiply the 7512 lost bytes per track times the 15 tracks allocated, there are 112680 total. Only full blocks are allocated on a track.

This is the difference between fully allocated tracks and tracks with a block size of 8192 (849960 - 112680).

by **santlou** » Fri Oct 31, 2008 4:26 pm

Dick,

Thanks. That works like a charm! I'm actually writing a REXX module that will use LISTCAT output to generate a DASD usage report. I know that there are more reliable ways of doing this, but in my organization, developers do not have access to SMF data.

Thanks for your help

by **Bill Dennis** » Fri Oct 31, 2008 6:37 pm

You should investigate DCOLLECT records for DASD reporting. It's described in the AMS for Catalogs manual (same as LISTCAT). This reports on all files, even the uncataloged ones. Better than trying to parse a LISTCAT report!

by **santlou** » Sat Nov 01, 2008 7:54 pm

Bill,

Thanks. Yes. I know about DCOLLECT. However, As an application developer in a large corporation, us developers do not have access to DCOLLECT. When I tried it, I got a nasty ACF violation. I've been a mainframe developer for over 27 years and it still boggles my mind that success access is restricted to systems support and not available to developers.

That's the primary reason that I'm using the LISTCAT output. I developed a REXX that does a bunch of stuff including generating a DADS usage report for specific high-level qualifiers, automatically Migrate files that do not need to be on DASD, automatically Recall files that are required, release free space in datasets that have too much free space, and other stuff.

Thanks for your input

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