rpinion865 wrote: > At a prior life, we got the zEDC cards on a z15, and turned that on >for PS datasets.
Just to clarify, every IBM z15, LinuxONE III, and higher model machine has on-chip zEDC (compression). It’s formally called the “Integrated Accelerator for zEDC,” and you can expand the zEDC part if you want to be more verbose. On-chip zEDC is included at no additional charge in these more recent machines. No zEDC cards required, no machine feature code required. Moreover, it’s not possible to carry forward the zEDC cards to the newer machine models even if you wanted to. I realize it’s not the major point of this thread, but here’s a quick comment about VSAM performance. I think it’s important to “sanity check” performance assumptions periodically because past assumptions often no longer reflect reality and time and technology progress. When I participate in such assessments (and write reports) I typically include an “expiration date.” I include a statement such as, “We recommend reassessing these performance metrics no later than April 30, 2028.” That sort of statement might be based on some educated guesswork, but I try to set a reasonable boundary in the circumstances. There’ve been lots of VSAM-related performance improvements over the years and decades, and they continue. zHyperWrite and the IBM Z Digital Integration Hub (zDIH) are only two examples. In terms of zEDC applicability to VSAM, just in case anybody needs the official documentation here it is (z/OS 3.1 link): https://www.ibm.com/docs/en/zos/3.1.0?topic=sets-characteristics-compressed-format-data The “Requirements for Compression” subsection is also relevant. There’s a lot of meaning packed into those two pages, more than usual I’d say. For example, these words are quite important: “A compressed format data set cannot be opened for update.” Those few words are doing some heavy lifting. I’d add that a non-compressed format data set (that can be opened for update) CAN contain data compressed with zEDC. As one example, a Java program can compress data with zEDC then store the compressed data in a data set (via JZOS for example). ————— Timothy Sipples Senior Architect Digital Assets, Industry Solutions, and Cybersecurity IBM Z/LinuxONE, Asia-Pacific [email protected] ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
