Do you want to install your z/VSE system on SCSI devices ?
Ingolf24 120000DRN3 Comments (2) Visits (4352)
Today I am late.
In April I posted already some information about z/VSE's SCSI support. We are getting more and more customer interest in that storage option. Therefore I want to give some more details about our SCSI support today.
z/VSE supports SCSI devices since 2005 native (in LPAR) as well as in z/VM guests. Yes, z/VM support SCSI devices too and Linux on System z since SCSI is supported on the mainframe.
z/VSE supports SCSI disk devices only, such as the IBM Storewize V7000, IBM XIV Storage System, devices available through the IBM SAN Volume Controller (SVC) or the IBM System Storage DS8000.
You can run z/VSE on SCSI only systems, that is you can install the system devices (DOSRES, SYSWK1) as well as your data devices on SCSI disks without a dependency on ECKD disks. Applications use FBA (Fixed Bock Architecture) channel programs or FBA interfaces to access SCSI disks. The FBA requests are translated to SCSI commands on low level I/O interfaces. Therefore the SCSI support is transparent to FBA or device independent applications. z/VSE supports up to 25 GB per volume, VSAM can use up to 16 GB per volume. If you are running z/VSE in a z/VM guest, you may use direct attached SCSI disks, minidisks or emulated FBA disks. Emulated FBA disks can have up to 2 GB per volume, which is the architected FBA size. Then z/VSE uses FBA I/O to those emulated FBA disks.
Data on FBA and SCSI devices are organized in blocks instead of tracks on ECKD devices. That is if you migrate from ECKD to SCSI, you have to change the EXTENT job control statements, which define the location of the data. Most applications are written device independent, but if an application does I/O via ECKD channel commands, it needs to be adapted. z/VSE. Fast Service Upgrade (FSU) from z/VSE systems running on ECKD to z/VSE systems on SCSI is not support. In that migration scenario you have to do a new install. FSU to a new z/VSE release from SCSI to SCSI environments is supported as you can expected.
I would start with the z/VS
Please let me know, if you have any questions.