True, no solution is as safe as shutdown/snapshot/restart in terms of ensuring consistency but I think it would be nice if there was some mechanism within Linux that would alert the kernel of this and would allow for a relatively consistent snapshot of the virtual machine, assuming perhaps we stop application servers databases on the host prior to snapshot. Then, we can at least minimize downtime for the server and reduce the resources necessary to bring the host back up. I am imagining trying to shutdown/restart dozens or hundreds of virtual machines to take a snapshot for DR would consume a fair amount of resources and slows down the process a lot. The bigger problem in my mind is that if you set this up to run unattended, then you have a much higher risk where a server has a problem upon restart.
I wonder if anyone would like to share their experiences with regards to automated shutdown/restart of linux guests for DR snapshot purposes. Aria -----Original Message----- From: Linux on 390 Port [mailto:[email protected]] On Behalf Of Rob van der Heij Sent: Thursday, August 30, 2012 11:43 AM To: [email protected] Subject: Re: LGR guest quiesce On 30 August 2012 17:11, 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? > No. It's perfectly possible that the Linux guest is moved from one z/VM LPAR to the other while it still has data in memory that's supposed to go out to disk (and it will eventually do that from its new location). 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/
