Paul, Perhaps, the manual doesn't explain this well. If you activate DVC in an existing dataclass, then the datasets that currently exist that have that dataclass defined will not benefit. However, once the DVC has been activated in the dataclass, then any new allocations will be able to exploit the advantages of DVC. This is what you just illustrated. You activated your DVC in you dataclas\; you defined your cluster with that dataclass; you changed the DVC value in your dataclass and it took effect immediately for your cluster without you having to reallocate it. Remember, to exploit DVC, the dataset has to be allocated after you first activate DVC.
Be careful as to what values you choose for the DVC. Too high of a value may have an undesired effect in your TIOT. Terry Traylor charlesSCHWAB TIS Mainframe Storage Management Remedy Queue: tis-ds-mainframe storage (602) 977-5154 WARNING: All email sent to or from this address will be received by the Charles Schwab corporate e-mail system and is subject to archival and review by someone other than the recipient. -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Paul Schuster Sent: Friday, November 03, 2006 10:49 AM To: IBM-MAIN@BAMA.UA.EDU Subject: DATACLASS DVC Hello: The manual z/OS DFSMSdfp Storage Administration Reference Publication No. SC26-7402 in chapter 7 'Defining Data Classes' there is this statement: "However, SMS does not retroactively apply your changes to previously allocated data sets." I have an example that contradicts this: I submit an IDCAMS define job that defines a VSAM cluster using a DATACLAS that has a Dynamic Volume Count (DVC) of 2. After this job completes, I modify the DATACLAS definition to have a DVC count of 9. I then submit an IDCAMS REPRO job that uses as output the dataset defined in the previous job. In a dump taken during this REPRO processing, I notice that the TIOT entry for this data set has room for 9 UCB's defined. Based on the statement in the manual ("However, SMS does not retroactively apply your changes to previously allocated data sets.") I would expect to see the TIOT have room for only 2 UCB's. Is this a problem with the documentation or with the SMS DATACLASS processing (or DVC processing) code? Thank you. Paul ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
