You don't mention your tape management system. With CA 1, we record both the "first" compression that the Dell/EMC performs (basic IDRC) as well as the raw data that was written by the application. Those two values would probably offer a good starting point for IBM. While the new "z" compression is better than IDRC; there is some correlation that can be calculated. Of course, once you start encrypting data your cache usage will increase substantially (nature of the beast). So, take that into account as well.
Russell Witt Broadcom CA 1 Architect -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Peter Sent: Tuesday, October 7, 2025 10:12 PM To: [email protected] Subject: Migration to IBM TS7780 Hello We are planning of migrating our non IBM VTS solution to IBM TS7780. So for sizing TS7780 VTS cache, Our IBM representative was asking our current VTS size. But the current VTS data is saving after compression and de-duplicated. Not sure how it will help IBM to size this solution from another VTS(non-ibm) which has different algorithm of saving data internally? Normally to size IBM VTS, what kind of mainframe data will be required? So that it can help the IBM to propose a sizing ? Any pointers on the above would be appreciated Peter ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
