Can you start up a snapshot on a cloned VM?

[Mandy1]

Hi everyone, I'm using ESXI4 and Vcenter, basically we have two hosts, one is TOM and the other is HARRY, I've set up a server A and TOM and used V center clone function to have an identical VM server B on HARRY. What I'm wondering is if I copy snapshots of server A on TOM to Server B on Harry, if Server A fails, can I start up Server A's most recent snapshot on Server B since they are identical? Thanks.

[ab_lal]

No,

Take separate snapshots of server A and B.

[Mandy1]

Thanks!

I was going to use the snapshots for Disaster recovey plan, if you cannot start up a snapshot on a cloned machine then we'll need a anothe way I guess, any idea why snapshots cannot be applied to a clone machine as I thought they were identical?

[FranckRookie]

Hi Mandy,

Welcome to the forum.

Even if it would be possible to copy the snapshot file itself, it will be hard work to script it and inject it in the second VM (modify virtual disk description file,... ). Just talking about the file copy, when you'll want to send it to the second server, it will be used and locked by the first machine. And don't forget that is not easy to maintain a home-made script!

Why not cloning the VM on a regular basis? Otherwise, you'd better to have a look at a real backup solution. Or why not looking at a shared storage device?

Regards

Franck

[Mandy1]

Hi Franck.

Well it is a long story, the DR project was planned before I started...

The company's not willing to pay for the share storage...

The engineer who originally planned DR thinks it would be enough for us just to use Vcenter by have two sets of identical servers on two different hosts and copy snapshots of the first set of servers to the second sets of servers on a regular basis, since they are identical, if one server on the first host fails the other one (which is normally powered off) can be started to revert to the most recent snapshot of the failed server, he believed snapshots can be started on the cloned server since they are identical, but so far I haven't managed to start a snapshot on a second server...

The original plan was

Having server A on host TOM and have an identical server B on host Harry (clone function in v center)

Take snapshots of server A regularly and copy these snapshots to server B everyd ay

If serverA fails, we can start up the most recent snapshot on server B, no shared storage, no third party application will be needed in this plan.

So this is not possible?

[FranckRookie]

I am not aware of any tool from VMware to copy just a snapshot. Either you clone the full VM or you buy a replication software. Is your VM so big that you can't copy it at night or during a week-end?

Sorry

Regards

Franck

[Mandy1]

I guess we can manually move the snapshots...but if these snapshots cannot be started up on a cloned machine then they don't really make sense because if the first server fails we cannot quickly replace the failed one.

One VM will be about 50G, it's not problem to copy it at night however I was told we will need to take snapshots every 15 mins to keep the data loss to minimum...

Like I mentioned the whole plan and hardware was all decided by I joined the firm, I was told if we copy snapshots to a cloned machine then if one server fails we can easily start the snapshot on the cloned machine.

I guess in the original DR plan, they look snapshots as whole backups which can be applied to a cloned machine, however if it is not possible in Vcenter to start snapshot on a cloned VM then the original DR proposal should be discarded, now we need to think about what to do if they are not willing to pay for shared storage or a replication software.

Just to confirm one more time, so snapshots can only revert to previous status on the original machine, if we copy them over to a cloned machine, these snapshot cannot be used on the cloned machine ?

Regards,

Mandy

[FranckRookie]

Every 15 mins ... It means that you generate a lot of data all day long. Keeping the snapshot for such a VM is not a good idea!

Forget about copying a snapshot file. If you want to copy it to your

second server, you need to stop the production VM to unlock it!

With no additional cost, the only solution is a regular clone.

Let's say we schedule it twice a day (lunch and midnight). If your application is so important, try to evaluate the cost of loosing half a working day of data. If it is more than the price of an entry level disk storage, then you have your budget! And you give security not only to this VM but to your full VMware infrastructure!

Good luck

Franck

Message was edited by: FranckRookie

Of course, if your second ESX is in another building or site, you need a backup or replication tool, not a shared storage.

[Mandy1]

Hi Franck,

Thanks for your detailed answer, I think I need to get the whole idea together and do a new DR plan...

Thanks again.

Regards,

Mandy

[sgrove]

Hi Mandy,

This idea just popped into my head, I have not tested this solution. Just starting the train and hopefully it spurs innovation from an expert. :smileyblush:

If your company will not purchase shared storage, will they provide you with another NIC for each host (if they don't already have two)? Then you can connect the hosts together, set the vMotion management network to run between the hosts, creating your failover solution. Either directly (w/ a crossover cable) or through a switch.Set the ports on the pSwitch (if needed), set a separate VLAN and IP addresses on the management NICs of the hosts, and configure the vSwitch on each host to reflect the VLAN and IP. This should work.

Now for the storage part:

Someone with more experience will have to take this, but there should be a way to create "shares" in your datastore, each looking at the other's physical disks.

If this is all wrong, please let me know.

-Steve

[Mandy1]

Hi Steve.

Thanks for that. Our license does not include V motion and our management thinks V motion is far too expensive, they prefer some tools within V center itself, e.g. clone, migrate etc etc

Their original plan was to copy snapshots from live machines to clone machines (powered off) ones on a regular basis so if anything happens, we can switch on the clone machine and start the most recent snapshots.

Unfortunately we haven't managed to start up a snapshot on a cloned machine, it may have something like GUID I guess, the snapshots idea sounds great but I cannot get it working, we will have a meeting with the engineer who originally said you can start up a snapshot on a clone machine next week, see what he says...

If we can have Vmotion I think having two NICs is a great idea to avoid expensive SAN, but since our license does not include V motion they are not willing to pay extra for Vmotion...

Regards,

Mandy

[sgrove]

Does your vCenter have the HA capability? What version of vCenter do you currently have?

[Mandy1]

I don't think so, what we have at the moment is

http://store.vmware.com/store/vmware/pd/productID.126843700/Currency.USD/?src=PaidSearch_Google_EMEA...

Regards,

Mandy

[sgrove]

From your link, I see that you do not have HA. But I do see that consolidated backup is an option. Check this .pdf out.

http://www.vmware.com/pdf/vi3_consolidated_backup.pdf

It was created for VI3, but should still be applicable in your situation.

[FranckRookie]

Hey Mandy,

Why not having your two VMs up and sending data updates regularly, from production to backup machine? Depending on the type of data you have, it could be more or less simple.

It is just another low-cost solution...

Regards

Franck

[sgrove]

What services are the VMs providing? Knowing this may help find a workable solution.

[Mandy1]

Eventually all servers will go virtual (that's the plan), DHCP, DNS etc.

At the moment we have Exchange 2007, SQL 2005, Microsoft Navision and a server that stores 300G of documents...

The company has paid extra to get some third party plug in for Microsoft Navision and if we just restore a backup, it doesn't work. Again the Navision server wasn't set up by internal technical team so no one knows what the problem is, at the beginning we were thinking of using Double Take to do full server protection for Navision server, because of budget we didn't get double take.

Also the server that stores 300G document is a bit of pain as well since we do not have such a big place to back up the whole 300G on a regular basis...

[Mandy1]

Hi Franck,

I have set up a domain controller on each host to enable AD replication, but the data hosted on Member servers I don't know how to enable replication, we'll need to protect exchange 2007, two SQL servers, one application server (Navision) and one server hosting 300G documents...

We have considered Double Take, Steel Eye, Server clustering but due to budget we didn't get them.

We are a team of two techies so any advice is welcomed!

Thanks again!

Regards,

Mandy

[FranckRookie]

Ouch! Serious infrastructure... Forget about "home made scripts"! You definitely need a real serious solution, either software for backup/replication or a storage device.

Good luck.

Franck

[Mandy1]

Well, our management think two techies are enough to maintain the company of 70 employees...

One can take phone call and resolve issues such as printers, PCs, and the other can be 'hands free' doing projects, and I got the job of doing projects...

Anyway, what backup/replication would you recommend?

What about VMware consolidated backup?

Regards,

Mandy