MVSFORUMS.com

[deepeshk79]

Hi,

I have to create a control card for a VSAM delete define. In doing this i have to allocate space for the VSAM. I know that for my VSAM file the

Total number of records expected = 932000
LRECL =650

Based on this i did the following calculation

======================================
LRECL= 650
TOTAL NO OF RECORDS = 932000
TOTAL BYTES REQUIRED = 932000*650 = 605800000.

ONE CYLINDER = 15 TRACKS = 15 * 55900 bytes = 838500 BYTES
TOTAL CYLINDERS THUS REQUIRED = 605800000 / 838500 = 723 CYLINDERS.

FOR VSAM FILES WE HAVE
PRIMARY + 255 * SECONDARY = TOTAL SPACE = 723

LET SECONDARY BE 2 CYLINDERS .....
THEN WE GET
PRIMARY + 255*2 = 723
==> PRIMARY = 723-510=213
HENCE WE CAN ALLOCATE THE SPACE AS (215,5) APPROXIMATELY.
========================================

Is this correct approach ??

Thanks,
Deepesh

[sandip]

Hi Deepesh,

For VSAM, you have to consider Key length, CI CA % and CISIZE also for better calculation.

Regards,
Sandip.

[kolusu]

Deepesh,

You approach is not right. You need to provide us with more details like CIsize, CI/CA percent, MIN/MAAX LRECL and keylength.

Download a free vsam space calculator from here.

http://www.talsystems.com/tsihome_html/techcorner.html

Hope this helps...

Cheers

Kolusu
_________________
Kolusu
www.linkedin.com/in/kolusu

[warp5]

Why didn't you just allocate it in Records instead of Cylinders?

[vapsvina]

Hi All,

In contunation with above question ..I have some queries

I want to allocate one VSAM cluster with following parameters...
Can anyone tell me,How to calculate the optimised size in cylinders??

LRECL=6250
Key Length=7
No of records= 8,50,000
CISZ=12288

Thanks,
Vaps

[kolusu]

vapsvina,

Did you try using the vsam space calculator from the 3rd post in this topic?

If you haven't then here is the calculation.