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What is the best solution, if any, for carrying out LVM style filesystem snapshots on OpenBSD?

Moo
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  • What is it you are trying to do? Create LVM snapshots? Create deduplicated backups? There may be a solution, but... since you are asking for help with OpenBSD, it might be easier if you fleshed out your needs a bit more, so it's easier to help you. Many people who use OpenBSD primarily may not be familiar with LVM style snapshots, and so have no idea what it is you actually want to do. – gabe. Aug 10 '10 at 04:18

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OpenBSD doesn't support UFS file system snapshots (afaik this a FreeBSD specific feature) and lacks block level snapshotting as well. You're out of luck unless some kind hypervisor or SAN implements the snapshotting for you. Unless you can remount the UFS file systems read-only, dump doesn't capture usable consistent states.

Andrew Schulman
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crest
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It's built in and called CCD. Look at section 14.18.1 of this FAQ page. It mentions a man page as well, but I can't link to that since I'm new.

EDIT: Not sure whether it supports snapshotting, but it may be of use.

koenigdmj
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Looks like your OPENBSD solution might be rsnapshot

rsnapshot is a filesystem snapshot utility for making backups of local and remote systems.

Any integrated feature of LVM other than doing the snapshot/restore may not be available, unless some other tool provides it.

Interestingly enough, rsnapshot is the example used in the OpenBSD FAQ on it's packages and ports.

Give it a try and hopefully it meets your requirements.

samt
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    Unfortunately, this doesn't work how you may be thinking. LVM snapshots are a point-in-time "snapshot" (for want of a better word) of the filesystem state. All future changes are saved in a copy-on-write volume until the snapshot is removed. rsnapshot, despite the name, doesn't make point-in-time snapshots: it simply provides a wrapper around rsync to allow hard linking of the same files/making historical backups etc. They are both very good tools (I use both regularly), but do not solve the same problem. – Andrew Ferrier Dec 22 '09 at 11:18
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UFS can do snapshots out of the box. I'm not really sure if this is what you want, though, as I understand LVM Snapshots to implement COW behavior, which UFS Snapshots won't give you.

juwi
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