On Thursday, 12/05/2013 at 12:07 EST, Doug <[email protected]> wrote: > That would be an interesting addition to SFS....
Like CP volumes, SFS disks are pre-formatted and so would not benefit from thin provisioning. (As mentioned, SFS already allows you to allocate more space than actually exists.) But DASD thin provisioning is really more suited to VSE and MVS, where the VTOC indicates what parts of the volume are unallocated. Software on the host is capable of triggering the control unit to reclaim the unused tracks, working with dataset scratch exits. You *could* play games where you only format the label of a user volume that contain minidisks. If your DASD vendor provides a CMS-based solution, then DIRMAINT or other directory manager exits could be used to trigger reclamation for DMDISK operations. (I suppose the exit could reach out to the controller API or SCIF to a Linux guest, if a Linux implementation is available.) So it's theoretically possible to take advantage of thin provisioning with ECKD on z/VM, but that would mean that you are deleting minidisks in quantities sufficient to make the effort worthwhile. 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/
