>From the Linux documentation https://www.kernel.org/doc/Documentation/s390/DASD it certainly seems that ECKD disks are well supported. That aligns with my recollection of experimentation of testing various zLinux in Hercules.
On Tue, Dec 17, 2019, 09:32 Laurence Chiu <lch...@gmail.com> wrote: > 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 > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
