TurnKey Linux Virtual Appliance Library

LVM Snapshots out of the Box?

larnold's picture

Changelog for the CORE says

Guided partitioning of root volume will default to 90% of volume group to support LVM snapshots out of the box.

I am wondering how, in Webmin hopefully, a Snapshot can be saved and if need be, later accessed.

I am assuming this is not a TKLBAM action, but rather a simple action on the Ap/Servers themselves.

I have one VM that is bare metal so I can't do my normal VM snapshots that work quite well.

thanks for any and all help.

Jeremy Davis's picture

Google suggests that what you request is possible

I've never done it myself but have a look here.

Landis Arnold's picture

I had the same link open actually...

That said, I couldn't make sense of it.  The only thing close I can find are

the Mounts in

Disk and Network Filesystems

but nothing that I can find on TKL about creating a Snapshot.  I wonder if there is a backend perhaps to this.

Landis Arnold's picture

Ok, it was there... under Logical Volume Management, but next...

I was misreading the instruction.

Snapshots are under : Logical Volume Management  (right side Webmin Menu)

Creating a Snapshot seems pretty easy.    Next is getting comfortable using the Snapshot.  It seems that one would need to interchange ones Boot Disk, but that doesn't seem logical.

It woiuld be nice if there is a simple command to "Revert to XYZ Snapshot" 

How might this take place?

Jeremy Davis's picture

LVM snapshots and VBox/VMware snapshots are different beasts...

Sorry about the delay in posting this. I wrote this some time ago (like days ago...) and was just cleaning up all my browser tabs and discovered that it was still in 'preview'... Here's what I posted:

Whilst they use the same terms, from my understanding they are not the same... By my understanding, an LVM snapshot is like a frozen (in time) image of the HDD (I know sounds the same so far...) But AFAIK they are not persistent, so if you wish to save a snapshot, then you actually have to then backup the snapshot (to a separate filesystem).

I think that Proxmox uses LVM snapshots for it's 'snapshot' feature (ie uses LVM snapshots, to create a snapshot more along the lines of what VBox and VMware mean) and that is how it can do full backups of servers while they are running (although they are faster and apparently more reliable if the VM is stopped). But Proxmox will not allow you to take VM snapshots unless you have alternative (and additional) filesystem location configured (eg a separate harddrive).

So whilst LVM snapshots are configured in TKL OOTB - to acheive your ends, you'll need to do a bit more work... Also please note that the above is simply my understanding from stuff I've come across in my travels. I haven't gone out of my way to research it and may have missed something...

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