On Tuesday, 03/20/2012 at 10:33 EDT, Rick Troth <r...@casita.net> wrote: > On Tue, Mar 20, 2012 at 9:56 AM, Alan Altmark <alan_altm...@us.ibm.com> wrote: > > SCSI-only configurations require some consideration: > > - You can't use the new Single System Image feature > > - You can't share the RACF database (not even with other VM systems) > ... > > I suspect that #1 is because XLINK support has not yet been ported to > FBA. Is that correct? (I won't say anything about VM having > supported FBA in other areas for thirty years. Too late!) > > Gotta wonder if #2 is further fallout from the XLINK challenge. > Someone should submit a req against this.
No, it's not about XLINK. As Neale says, for SSI, CP uses atomic channel programs to "compare and swap" on the volume that contains the Persistent Data Record (PDR). That logic isn't available for SCSI. As far as RACF database sharing goes, there are three issues: 1. Lack of RESERVE/RELEASE for virtual FBA. 2. Lack of real RESERVE/RELEASE for SCSI in the SCSI command set CP must use (advisory locking only, I believe). 3. Use of CMS files to contain the database. RACF support for FBA was not written with the idea that the database would be shared. Significant RACF updates would be required, even after the CP restrictions were lifted. Alan Altmark Senior Managing z/VM and Linux Consultant IBM System Lab Services and Training ibm.com/systems/services/labservices office: 607.429.3323 mobile; 607.321.7556 alan_altm...@us.ibm.com IBM Endicott ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
