I wonder if doing a 'sync' on Linux just prior to the STOP would help cut down on anything in the buffers?
Scott Rohling On Fri, Aug 31, 2012 at 6:52 AM, Aria Bamdad <[email protected]> wrote: > Thanks for the link to that document Marcy. I think the CP STOP/BEGIN > method would be the best solution for when you want to take a flashcopy of > a > live and still running guest. Doing this plus normal file level backups > would be a pretty safe DR solution. It also would cut down on the time a > guest is down and eliminate the need for a shutdown/restart. > > -----Original Message----- > From: Linux on 390 Port [mailto:[email protected]] On Behalf Of > Marcy > Cortes > Sent: Thursday, August 30, 2012 2:50 PM > To: [email protected] > Subject: Re: LGR guest quiesce > > The suspend/resume thing exists already - > > http://www-03.ibm.com/support/techdocs/atsmastr.nsf/5cb5ed706d254a8186256c71 > 006d2e0a/57e3c8123412429186257910006ab443/$FILE/l0wadp00.pdf > > The CP STOP command may also be good enough. Yes, you could have lost data > in open files, but this would be no different that say a loss of power. > You'd fsck and go on when you booted back up. You wouldn't have the issue > of disk A being out of sync with disk B which you'd get flashcopying a live > system. > > > Marcy > -----Original Message----- > From: Linux on 390 Port [mailto:[email protected]] On Behalf Of > Scott > Rohling > Sent: Thursday, August 30, 2012 8:28 AM > To: [email protected] > Subject: Re: [LINUX-390] LGR guest quiesce > > I don't think the disk snapshot from a freeze would be any better in terms > of data integrity. You're still snapshotting a disk with things like open > files - and the guest is in an unknown state processing wise. > > If there was a facility to restore disks and then resume processing where > the guest left off - it might work.. But you need something to dump and > restore memory/pages/etc as well. Sort of like 'hibernate' on a laptop. > > Scott Rohling > > On Thu, Aug 30, 2012 at 8:11 AM, Aria Bamdad <[email protected]> wrote: > > > Just curious, could this functionality be used somehow to allow for a > > **consistent** disk snapshot using flashcopy for a live Linux guest? > > What I mean is that currently, we have to shutdown the guest, do the > > flashcopy and then restart the guest. Is there a way we can tell the > > Linux guest to freeze, take a snapshot of the disks and then resume? > > > > -----Original Message----- > > From: Linux on 390 Port [mailto:[email protected]] On Behalf Of > > Rob van der Heij > > Sent: Thursday, August 30, 2012 7:47 AM > > To: [email protected] > > Subject: Re: LGR guest quiesce > > > > On 30 August 2012 11:43, Lu GL Gao <[email protected]> wrote: > > > > Linux guest move its memory to target z/VM member during relocating. > > Then > > > it quiesce and resume on target z/VM. > > > How to understand "quiesce"? What state of linux when it is in > > > quiesce time? Is idling? shutdown? or something? > > > > > > > See it as "frozen while running" - as long as Linux is actually > > running, it may change memory that z/VM already copied over, so z/VM > > will copy it again, and again... To stop that, finally the guest is > > frozen for a very short period, not making any further changes. That > > gives z/VM time to copy the last bits and the guest then continues to > > run on the other side, at the very instruction where it was frozen > before. > > Linux will observe that some time passed where it did not run, but > > that's normal in time sharing. > > > > Rob > > > > ---------------------------------------------------------------------- > > 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/ > > > > ---------------------------------------------------------------------- > > 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/ > > > > ---------------------------------------------------------------------- > 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/ > > ---------------------------------------------------------------------- > 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/ > > ---------------------------------------------------------------------- > 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/ > ---------------------------------------------------------------------- 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/
