Sorry about my late reply, been a very busy summer. With CA 1 Flexible Storage (CA 1 R15.0), you can now compress and encrypt tape data using the Pervasive Encryption key (specified in the external-security rule, the SMS DataClass or the JCL). The compression is done with z/EDC (much like specifying ZCOMPRESS on the ADRDSSU backup) and the encryption of course is done with AES256 encryption. The advantage is this is all done in the zIIP engines (if available) - so uses a LOT less CPU cycles than ADRDSSU with the ZCOMPRESS option.
Granted, if the disk file itself has been compressed/encrypted before being backed up and is not decrypted as part of the backup operation - this is redundant. Just like IDRC, de-duplication or z-compress in the TS7700 is useless if applied to already encrypted files. However, I have found that a LOT of sites are not yet exploiting PE very much yet. And when they do, often times they do not compress the data first (which makes cache usage increase since the data will never be able to be compressed after encryption). Russell Witt Broadcom CA 1 Architect -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of John Young Sent: Saturday, April 15, 2023 8:48 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Tape compression and modern encryption facilities. Although my post today is probably rhetorical question, I wanted to find out whether this matters anymore or not. Back in the late 2000's, IBM developed encryption facilities within the tape drives, as this is also where compression was being performed. The idea was that compression of data must occur before encryption, as encrypted data does not compress well, and obviates the use of compression. Nowadays, we've got pervasive encryption on z/OS. As a result, any data that is backed up (for instance, ADRDSSU/FDR), is already encrypted. Also, we now have zEDC, to compress data prior to storage, typically on disk. To my question: With all the encryption and compression being performed on disk, to what degree does TAPE COMPRESSION matter anymore? ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
