> Well, personally, I think it would be better to address this totally > from the Linux side. That is a "program" or script which could tell all > processes: Harden your data to disk and suspend processing. The process > would respond by hardening any data in its cache, then "do something" so > that it would become nondispatchable to the zLinux kernel. After all > processes have "done this something", the program/script would then > harden all cached information to disk. It would then do the "snap" > itself (or even do a DIAG 8 to tell z/VM to do it, if necessary). Once > the "snap" is done, it would tell all processes: "restart processing". > Or tell the kernel to release the processes which went into that > voluntary nondispatchabel state previously mentioned.
A lot of this function is already in EVMS and LVM -- which at least attempt to get the disk into a consistent state before doing snapshots. Check out evms.sourceforge.net -- even if you use LVM or MD or other disk stuff, EVMS is worth looking into just as a control interface to manage the process (and note the ability to generate generic snapshots works with lots of different disk management techniques). It is fairly simple to automate the snap process logically from within the guest with EVMS (there are nice linemode commands that humans can understand (as opposed to the LVM syntax)), and then have the hardware do the deed for a image backup. > I do not really see the above happening, however. It would be a change > in the kernel which is specific to zSeries processing. I am under the > impression that the "kernel gods" want to avoid hardware specific mods > as much as possible. Actually, I don't think that's so unreasonable. All the virtualization solutions are going to face this problem eventually. We're just leading the pack again...8-) ---------------------------------------------------------------------- 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
