> if you write a 32K block to an emulated 3390 track, the balance of the space will be wasted
Is that true? (Serious question -- everything I know about DASD management could be written in one paragraph of an e-mail.) Sure, it wastes "virtual" space on the emulated 3390 track, no doubt, but aren't modern storage arrays smart enough not to waste the real disk space that you are paying for on empty 3390 track space? Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Ron Hawkins Sent: Friday, May 19, 2017 4:47 PM To: [email protected] Subject: Re: SDB (system determined Blksize) Lizette (OP), I would not recommend going to 32K as a blocking factor. Generically speaking, all three vendor emulate a CKD track, allocating up to 64KiB of space for every track. Whether you use a regular formatted volume, or thin provisioning (DP-VOL in Hitachi speak), if you write a 32K block to an emulated 3390 track, the balance of the space will be wasted. Ipso fact you will use 41% more space for the same amount of data at half-track. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
