On Thursday, 08/16/2012 at 03:02 EDT, "McKown, John" <[email protected]> wrote: > I had forgotten about iSCSI, as mentioned by another person. I don't think that > z/VM supports iSCSI attached DASD as a DASD device. If true, you'll still need > some channel attached disk for z/VM and, I think, the z/Linux "boot" DASD. I > don't know if z/Linux under z/VM can boot from an iSCSI device. Once z/Linux is > up, then it can act as the iSCSI initiator, I would hope.
Neither z/VM nor LPAR supports iSCSI for its own use (and hence not as a host boot device). But, as you note, once Linux has booted from SCSI, DASD (ECKD or FBA), FTP, or removable media, it is free to use NAS as it wishes. People wishing to compare Linux storage alternatives may be interested in http://www.vm.ibm.com/perf/reports/zvm/html/520lxd.html. (iSCSI is not among the tested alternatives.) While that report just shows relative performance, an older IBM white paper I saw showed FCP SCSI data transfer rates on the order of 800 MB/s (read-only, of course). The point being that you need 10Gb OSAs to even think about getting up to that kind of speed, so adjust expectations accordingly and consider that you will probably need QoS controls to ensure reliable (consistent) throughput. 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 [email protected] IBM Endicott ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] 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/
