VSAM is VSAM. Whether it is an MQ PSID, DB2 Table, Native Vsam. They generally fall under the same rules.
Do you want the dataset to expand across volumes? Or stay on one volume? Do you want it to be only 4GB, or can it be a VSAM that grows? Extended means go beyond the 4GB limit. Do you have a need to do this? If so, then you need to allocate with EA/EF for the VSAM. If you do not want to expand beyond 4GB limit then the allocations will go up to the 4GB limit and fail the extent when you try for that extra byte over 4GB. So, what is your requirements. If you allocate a VSAM dataset with PRI and SEC then it will expand up to 4GB if it is not extended as well as possibly going across multiple volumes. However, if you only allocate a PRI with SEC = 0 Then it should stay within that one allocation. What type of allocation do you want? I understand you want to allocate for 4GB, but why? You could let the VSAM data set grow naturally as needed. Do you have a way to control the VSAM file so it will only use this amount of data? I am thinking that if you try to do this, you may have REORGs that will need to be done. Remember, CISIZE, CASIZE, what type of VSAM (KSDS, ESDS, RDS, Linear) will all allocate slightly different. Could you explain the application in a little more detail. I think it will help in providing a better targeted answer. I am not sure what you mean by OAM datasets. Are you talking about the TCDB or other OAM Files? If so, I think they have unique requirements. Lizette > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:[email protected]] On > Behalf Of willie bunter > Sent: Wednesday, October 22, 2014 6:35 AM > To: [email protected] > Subject: Re: QUESTION ABOUT VSAM / VSAM EXTENDED > > Thanks to everybody's input. However, I still don't have a firm answer. What is the > maximum amount of cylinders should I be able to allocate for a VSAM DSN without > having to make it EXTENDED. > > Would this be the same critera for OAM dsns as well? > > -------------------------------------------- ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
