On 13-04-07 03:00 AM, Stephan von Krawczynski wrote: > On Sat, 06 Apr 2013 14:32:34 -0700 > Geoff Nordli <geo...@gnaa.net> wrote: > >> On 13-04-06 01:46 PM, Stephan von Krawczynski wrote: >>> On Sat, 06 Apr 2013 10:50:13 -0700 >>> Geoff Nordli <geo...@gnaa.net> wrote: >>> >>>> I would say that the vbox snapshots are not the path you want to take >>>> for backups. VBox snapshots are great when experimenting with software, >>>> or creating a library using a base images. If you do a VBox snapshot >>>> online, then you also have a .sav file, and you have to wait for the >>>> save/resume to complete before it can come back online. If you can >>>> afford downtime, then I would power off the VM to get a consistent state >>>> of your data. >>>> >>>> Other people may be able to chime in here, but if you looking at using >>>> it for backups, then pausing the machine, and using LVM may be something >>>> that works, because after you take the backup, you delete the lvm >>>> snapshot. You will need to delete the backup though because LVM doesn't >>>> scale well for snapshots. In the past I used LVM and raw disks to do this. >>>> >>>> Geoff >>> Hm, but your script does suspend/resume the vm, too. I cannot see a big >>> difference to a vm snapshot ... ? >>> >>> >> The script uses the virsh suspend command which just pauses the VM >> temporarily until it is resumed, which is pretty much instant. >> >> http://www.centos.org/docs/5/html/5.2/Virtualization/chap-Virtualization-Managing_guests_with_virsh.html >> >> Whereas the vbox "savestate" when doing a snapshot takes a lot longer, >> because it writes out the active memory to a saved state file. > Well, if you only suspend the guest, then take a backup from the vdi (with > whatever method) you will not end up in a consistent backup. Think of a mysql > database where you just suspended the guest right in between some write > action. your database file has a good chance to be corrupted that way. > On the other hand, if you take a snapshot of the guest and backup this > chances are better you'll be able to resume the guest later on during > restore, not? >
Yes, with LVM, I would prepare any hot applications for backup just to make sure. Note, pausing the disk will flush vbox cache: https://www.virtualbox.org/pipermail/vbox-dev/2011-June/004207.html For my MySQL maybe something like this: http://www.lenzg.net/mylvmbackup/ where they put a read lock on all the tables, and flush the cache. For windows you want to use VSS. You can execute scripts inside a guest os using guestcontrol, or use SSH before you pause the host. I am worried less about corruption with ZFS because it writes data in transaction groups and uses a COW format so data is never overwritten. Another note, you want to make sure you disable the "ignoreflush": http://www.virtualbox.org/manual/ch12.html#idp20230944 ------------------------------------------------------------------------------ Minimize network downtime and maximize team effectiveness. Reduce network management and security costs.Learn how to hire the most talented Cisco Certified professionals. Visit the Employer Resources Portal http://www.cisco.com/web/learning/employer_resources/index.html _______________________________________________ VBox-users-community mailing list VBox-users-community@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/vbox-users-community _______________________________________________ Unsubscribe: mailto:vbox-users-community-requ...@lists.sourceforge.net?subject=unsubscribe
