Slightly outside my area of knowledge but since z/VM is the OS that is attached to the DS8K, it's doing the physical IO. And this is usually FICON.
The Linux guest is being provided a virtual disk from z/VM so the disk protocol is probably not relevant. Plus I don't think a Linux guest can actually see a CKD volume - it would all look ike FB. Others feel free to chip in here On Tue, Dec 17, 2019 at 4:45 PM Peter <dbajava...@gmail.com> wrote: > I believe giving a dasd 3390(CKD) to linux guest and internally it converts > that into SCSI. > > So having SCSI alone for Linux guest would be better interns of performance > ? > > On Tue, 17 Dec, 2019, 12:54 AM Laurence Chiu, <lch...@gmail.com> wrote: > > > I asked my z/VM and DS8K person this question and he wasn't sure what you > > were asking. > > > > He said he defines all the storage on his ds8k box as CKD though he could > > have chosen fixed block and assigns all that storage to the z/vm host. > > > > For each Linux instance that requires storage he just carves out the hunk > > of storage on Z/VM and assigns it to the Linux guest . > > > > SCSI is irrelevant because the Linux guest is virtual and doesn't need to > > know about the disk protocol. And his z/VM host is connected via FICON. > > > > He said the only time one might need to go back to the ds8k is if some of > > the storage on that box hadn't been defined and needed to be redefined > and > > then attached to the z/vm host. But he's never had to do that in 10 years > > of running that system. > > > > > > > > On Tue, Dec 17, 2019, 7:28 AM Peter <dbajava...@gmail.com> wrote: > > > > > Hello, > > > > > > Could someone please recommend a manual which describes step by step > > > procedure to define SCSI on DS8K. > > > > > > I need this procedure to define SCSI disk for my Linux guest running on > > > zVM. > > > > > > Peter > > > > > > ---------------------------------------------------------------------- > > > 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 > > > > ---------------------------------------------------------------------- > 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
