Portal | Manuals | References | Downloads | Info | Programs | JCLs | Master the Mainframes
IBM Mainframe Computers Forums Index
 
Register
 
IBM Mainframe Computers Forums Index Mainframe: Search IBM Mainframe Forum: FAQ Memberlist Usergroups Profile Log in to check your private messages Log in
 

 

Space calculator - Number of records reqd

 
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> JCL & VSAM
View previous topic :: :: View next topic  
Author Message
chaitanya.sameer

New User


Joined: 13 Mar 2007
Posts: 2
Location: USA

PostPosted: Tue Mar 13, 2007 6:05 am    Post subject: Space calculator - Number of records reqd
Reply with quote

Hi -

Can anybody provide me an idea about how to calculate the number of records per dataset provided the properties of a dataset. Do we have any tool as such to do the same?

For example we have a GDG with the following attributes:
//DOCM DD DSN=xxxx.xx.xx..xxxx(+1),
// DISP=(NEW,CATLG,DELETE),
// SPACE=(15000,(30,6),RLSE),
// AVGREC=K,
// DCB=(CU.GDG,
// LRECL=15000,
// RECFM=FB)

The disk model is 3390. I want to get the maximum number of records that could be inserted in this GDG. Your help on this is appreciated.

Thanks in advance..!
Back to top
View user's profile Send private message

dick scherrer

Site Director


Joined: 23 Nov 2006
Posts: 19270
Location: Inside the Matrix

PostPosted: Tue Mar 13, 2007 8:01 am    Post subject:
Reply with quote

Hello,

You best information source is to talk with your storage management people. The definition you've provided will not store many records.

Your jcl says to allocate space in blocks of 15000 bytes and that lrecl is 15000. If your lrecl and blocksize are the same you have asked for primary space for 30 records with some number of secondaries (6 at a time). How many secondaries you may allocate depends on your environment. Again, this information should be easily gotten from the storage management people.

It is more typical to estimate space on the basis of lrecl * # of records.
Back to top
View user's profile Send private message
chaitanya.sameer

New User


Joined: 13 Mar 2007
Posts: 2
Location: USA

PostPosted: Tue Mar 13, 2007 8:06 am    Post subject: Re: Space calculator - Number of records reqd
Reply with quote

Since the block size and the LRECL are the same; Primary space of 30 and AVGREC=K implies the number of records to be 30K in this dataset. Apart from this (i.e. after the 30K records) I believe the secondary extents come into picture.

Please correct me if I am wrong.
Back to top
View user's profile Send private message
dick scherrer

Site Director


Joined: 23 Nov 2006
Posts: 19270
Location: Inside the Matrix

PostPosted: Tue Mar 13, 2007 8:33 am    Post subject:
Reply with quote

Hello,

Sorry 'bout that - missed that parameter icon_redface.gif

Yes, after the primary, the secodary allocation comes into the picture.

Depending on your site, the number of possible secondaries may vary. Also, when a secondary is allocated, it may or may not be the full size.

As i posted earlier, it is more typical to calculate space based on file size rather than pick some allocation definition and then try to figure how many records it will hold.
Back to top
View user's profile Send private message
View previous topic :: :: View next topic  
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> JCL & VSAM All times are GMT + 6 Hours
Page 1 of 1

 

Search our Forum:

Similar Topics
Topic Author Forum Replies Posted
No new posts Removing Duplicates based on certain ... chandracdac DFSORT/ICETOOL 8 Fri Dec 09, 2016 4:40 am
No new posts Limit duplicate records in the SORT pshongal SYNCSORT 6 Mon Nov 21, 2016 12:54 pm
No new posts How to split the records using the am... vnktrrd DFSORT/ICETOOL 24 Fri Oct 28, 2016 7:33 pm
No new posts Sort records based on numeric field. Alks SYNCSORT 2 Wed Oct 19, 2016 10:14 pm
No new posts abend sort based on count records in ... anatol DFSORT/ICETOOL 5 Mon Oct 17, 2016 10:10 pm


Facebook
Back to Top
 
Mainframe Wiki | Forum Rules | Bookmarks | Subscriptions | FAQ | Tutorials | Contact Us