Space allocation when expanding the VMF.
Article ID: 191980
Updated On:
Products
Issue/Introduction
Blocking the VMF can help reduce the run time of CATTRS and reports. This will help you determine the allocation that you need and the maximum size for the VMF.
The VMF allocation has been a hit or miss proposition at its best in the
past. We have found many VMF that were extremely over allocated or worse, under allocated.
Environment
Cause
The VMF allocation has been a hit or miss proposition at its best in the past. We have found many VMF that were extremely over-allocated or worse, under-allocated.
Resolution
Here's the formula the will determine how large to allocate the VMF.
Execute proc CATVMFB and get the following totals from the TLMS048 report:
TOTAL BASE RECORDS WRITTEN.............
TOTAL MVL RECORDS WRITTEN................
TOTAL MDS RECORDS WRITTEN..............
TOTAL AUXILIARY RECORDS WRITTEN........
As far as the allocation goes, if you block the VMF at 5000 bytes, you will get 1500 records per cylinder. To compute the number of records in the VMF, just add up the number of volumes in all the ranges, add the number of MVL/MDS/AUX Records defined and add about 100 records for various internal recs.
In the example below, the VMF will be blocked at 5,000. Divide by the number of records per cylinder. See the table below.
Take the totals from the latest VMF backup and add up the four totals:
TOTAL BASE RECORDS WRITTEN............. 2,152,880
TOTAL MVL RECORDS WRITTEN................ 19,742
TOTAL MVL RECORDS WRITTEN................ 19,742
TOTAL MDS RECORDS WRITTEN.............. 1,980,772
TOTAL AUXILIARY RECORDS WRITTEN........ 249,486
------------
4,402,880
+ 100 - Internal records.
------------------
4,402,980
/ 1,500 - Blocked at 5,000
------------------
2935 CYLS, round up to 3000 CYLS.
******
Updated VMF:
TOTAL BASE RECORDS WRITTEN............. 2,152,880
TOTAL MVL RECORDS WRITTEN................ 19,742
TOTAL MDS RECORDS WRITTEN.............. 1,980,772
TOTAL AUXILIARY RECORDS WRITTEN........ 249,486
New Aux records - 2250000 to 4000000... 1,750,000
Reduce range 100000 100999 .... - 9,000
Increase range 100000 129999........... 20,000
------------
6,163,880
+ 100 - Internal records.
------------------
6,163,980
/ 1,500 - Blocked at 5,000
------------------
4109 CYLS, round up to 4300 CYLS.
For other blocksizes:
500 - 735 per Cylinder
1000 - 1020 per Cylinder
2000 - 1260 per Cylinder
3000 - 1350 per Cylinder
4000 - 1440 per Cylinder
5000 - 1500 per Cylinder
27000 - 1620 per Cylinder *** demonstration only - do not use ***
Your VMF file can not exceed 4369 cylinders. When blocked at 5000 that is
6,553,500 records. This includes any control records for TLMS, all of the
VOLUME records and the AUX records.
Steps to add a new range.
(1) Run PROC CATVMFV and correct all errors.
(2) Stop all tape processing on all LPARS. Bring down CTS.
(3) Run PROC CATVMFB to backup the VMF.
(4) Update TLMSIDCK in the CTAPOPT with new ranges
(5) Run PROC CATVMFRS to restore the VMF. This will add the changes.
(6) Run PROC CATVMFXI to rebuild the index.
(7) Start CTS and verify you can see the new volume range within TLMS.
Simply browse the new volumes with the TLMS ISPF panels.
*
Notes:
You can back up the VMF in CATVMFB to disk if you like.
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