Re: [tlug] vmware, linux, snapshots

[Romeo Theriault <romeo.theriault@example.com>]

On Mon, May 16, 2011 at 00:56, Darren Cook <darren@example.com> wrote:
>
> One of my clients is using vmware to run quite a few virtual servers,
> mostly windows.

Which version of vmware are they running? ESX, esxi, vsphere? They all
have differing capabilities.

> They apparently don't have the more expensive license
> that allows "hot snapshots" (which would allow moving a virtual server
> from say one physical machine to another in a matter of minutes).

I *think* you might be mixing up two different features here. The
vmware ability to "move" one virtual server to another live is called
"VMotion". This feature does require the enterprise license. But the
ability to take vmware snapshots of the VM's is included in the free
vmware product, esxi.

> Instead they can take a snapshot once a week, and it is quite a slow
> process. But, apparently, they cannot do even this for linux.

We take vmware snapshots of our linux VM's all the time, not sure why
they wouldn't be able to do this. Taking the snapshot itself doesn't
take long, just a few moments, but if you let the VM run with the
snapshot for a while (a week) then it can take a while to remove the
old snapshot. Because vmware stores the data changes after the
snapshot in a log file that then need to be merged back into the main
vmdk when you go to remove the snapshot.

>
> For this particular linux server they are setting up, there will be the
> actual server, and then another server with the same spec that won't be
> used, it just exists to take over if the first one goes down.

Is this bare metal vmware hypervisor or are they running linux as the
primary OS on the machine which then runs vmware software which hosts
the VM's?

Depending on where and what their datastore sits on they may be able
to get creative and take SAN/NAS based snapshots of the VM's, taking
vmware out of the picture entirely. I'm assuming they're using some
sort of shared storage if they have two machines that are setup in a
failover mechanism. What does the shared storage machine run? Can they
take snapshots their and then mount the snapshot on another machine
which would then back up the VM's?

>
> Are there any good vmware options here? Or is running rsync regularly,
> to copy from main to backup server, the best choice?
>
> Darren
>
> --
> Darren Cook, Software Researcher/Developer
>
> http://dcook.org/work/ (About me and my work)
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>
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--
Romeo Theriault