Date: Mon, 8 Dec 2014 10:08:52 -0800 From: Alfred Perlstein <bright@mu.org> To: John <freebsd-lists@potato.growveg.org> Cc: fs@freebsd.org, freebsd-virtualization@freebsd.org Subject: Re: backups of bhyve images Message-ID: <33053EB5-91C5-4036-8CC2-34103E33A0FA@mu.org> In-Reply-To: <20141208163358.GA52969@potato.growveg.org> References: <20141208163358.GA52969@potato.growveg.org>
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On Dec 8, 2014, at 8:33 AM, John wrote: > Hello list, > > I have a few questions about creating backups to be stored offsite. > > If a guest is running, can I compress the image without it becoming > inconsistent? If not, can it be copied without it becoming inconsistent? > By inconsistent, I mean will I see weird effects and broken files if the > backup is restored? Previously I've shut the VM down to avoid this, > before archiving. > > I have each image on its own (external to the image) ZFS filesystem. > Internally the image is using ufs if freebsd, ext3fs if linux. Would > using some ZFS method of duplication be better? In this case, would the > image become inconsistent? > > Basically, what I want to do is to run accurate backups without shutting > down and restarting the VM. Is this possible? If it isn't, I think the > only alternative is to make a script that shuts the vm down, copies it, > restarts the vm then runs its compression and backup-over-ssh routine. [[ adding fs@freebsd.org in case I'm wrong ]] If you are using UFS internally to the VMs then you'll need to send a snapshot that is consistent. If you are just copying the files out from under a running vm you are going to get spaghettios for a filesystem if you try to recover as you need a true point in time snapshot. I think a few better options would be: 1) Inside the VM create a UFS snapshot then dump that externally using tools. 2) Create the UFS snapshot, then make sure that the file/vzol is snapshotted using zfs. 3) Just snapshot the underlying zvol you've made the UFS image on and send that (you'll get a dirty FS on restore, but it *should* be recoverable with a simple fsck) 4) Use zfs internally to the vm and send/receive the internal zfs. option 3 is the least safe imo as you can wind up with filesystem "angry". in case 1 and 2 you'll have UFS snapshots that should be "OK" to restore from. in case 4 you are also doing snapshot, but you switch to ZFS. -Alfred
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