An interesting question, Ken. Don't know about the settings but 2 observations:
I very rarely see significant USAGE of CFW in data - but it might be enabled. I always see significant Cached Writes (a la DFW) in data - sometimes as much as 50% of cached reads. But I couldn't tell you if it's possible to disable it. So, given your motivation was to check your controllers are set up properly in these 2 regards they almost certainly are. And I'd use RMF Cache Activity Report / SMF 74-5 (and other records and downstream tooling) to check how they're doing. A question in return to IBM-MAIN: Is it possible to set the size of the DFW portion of the cache? Used to be called NVS size but that's such an old term it's probably not used anymore when it comes to actual machine configuration. Cheers, Martin Martin Packer, zChampion, Principal Systems Investigator, Worldwide Banking Center of Excellence, IBM +44-7802-245-584 email: [email protected] Twitter / Facebook IDs: MartinPacker Blog: https://www.ibm.com/developerworks/mydeveloperworks/blogs/MartinPacker From: Ken Leidner <[email protected]> To: [email protected], Date: 10/31/2012 02:55 AM Subject: DASD and Cache Fast Write & DS8800/DS8700 Sent by: IBM Mainframe Discussion List <[email protected]> Does setting the DASD FW or Cache FW on or off still exist on the DS8800/DS8700 devices. I know when they first came out for a 3990-6 controller, the performance different was night and day. But on the newer devices isn't it always on? Can I really still turn it off? Do I still need to check to make sure it is on? Ken Leidner [email protected] ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN Unless stated otherwise above: IBM United Kingdom Limited - Registered in England and Wales with number 741598. Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
