Based on what I've read the MCDS technically can only be on one volume. Now you can have up to 4 MCDS datasets in the HSM configuration. Each dataset can only be on 1 volume. In our shop we have 4 MCDS datasets defined to HSM and each is on its own volume. We have several lpars sharing the HSM environment and yes we use RLS to help control things.
From an IBM manual: When a control data set is defined on one volume, it is defined as a VSAM KSDS cluster. When the control data set is defined on two to four volumes, it is defined on each volume as a unique VSAM KSDS cluster. DFSMShsm can manage the control data set even if it consists of several VSAM clusters. Based on your calculations for the space required to define your control data set, you determine the number of volumes that are required and, therefore, the number of required clusters. The MCDS and BCDS may each be on more than one volume; the OCDS can be on only one volume. Thanks.. Paul Feller AGT Mainframe Technical Support -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Hervey Martinez Sent: Tuesday, December 18, 2018 11:51 AM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Multi-volume HSM MCDS [EXTERNAL] The MCDS is taking up a full mod-9 and it is growing. I'm looking at expanding the file to be multi-volume and wondering if this can be done without converting CDS to RLS? Done some searches but don't really come up with anything. How would this be expanded to multi-volume. Would the definition just be, let's say 20,000 cylinders and make sure there are two mod9 volumes available? One option would be to move it to a Mod-27 but not sure if such a volume is available at our DR site. Anybody have any ideas? ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- Please note: This message originated outside your organization. Please use caution when opening links or attachments. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
