Snapshots & Backups

[curiousagain]

Hi all,

I have some questions regarding snapshots and backups (data recovery tool), please try to help:

1. If I'm taking snapshots of VM with 10 GB hard drive every day, will the folder with all snapshots exceed the 10GB size eventually? If yes, how will I know that my storage will be enough?

2. Do I need to keep all snapshots or can I delete all of them and keep only the last one? If I can keep only the last one, is it possible that this snapshot will be bigger than 10GB?

3. Regarding Backups, what are the differences between snapshots and backups (data recovery tool)?

4. If I'm planning to backup servers (data recovery tool) over the network, will it extremely load it?

Thanks in advance.

[ShaneWendel]

1. Yes, and I'll tell you right now that you don't want to be doing this, as it will greatly impact performance. I would never keep more than one for any significant amount of time. The amount of space used by the delta files is totally dependent on how much changes from the base image.

2. You can delete individual snapshots.

3. Snapshots are not a backup, as they require the original state to exist. Think of them more like System Recovery in Windows. Plus, everything exists on the same storage. A true backup would be vDR or VCB to seperate storage.

4. It will use as much throughput as you allow it to. You can put the vDR appliance on a vSwitch where traffic shaping is enabled.

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Shane Wendel, VCP

[curiousagain]

Thank you very much for the helpful information.

Some more questions:

1. Is the delta taken from the original state or from the last snapshot?

2. Do I need to take the snapshots after deleting the previous one or I can take snapshot and then delete the previous one?

3. Is it possible that one snapshot will be bigger than the hard drive of the VM?

4. So if I'm using VDR I'll get a complete machine for every backup, right? Isn't it too "heavy" for the network (the backup is done on remote FTP)?

[vikunmittal]

1. If there are any existing snapshots then the last delta file points to the last existing snapshot(delta file), else it points to the base disk.

2.You can keep multiple snapshots at any time. You may delete upto a particular snapshot( this will delete this snapshot and the ones taken before this one), else you may delete all and commit all to the base disk.

3.Its possible but not recommended.

[AntonVZhbankov]

>1. If I'm taking snapshots of VM with 10 GB hard drive every day, will the folder with all snapshots exceed the 10GB size eventually? If yes, how will I know that my storage will be enough?

Each snapshot can grow up to 10GB depending on disk load. So in worst case Total VM size = (NumberOfSnapshots +1 ) * VMSize

>2. Do I need to keep all snapshots or can I delete all of them and keep only the last one? If I can keep only the last one, is it possible that this snapshot will be bigger than 10GB?

Keep only significant points you want to be able to restore to, all other snapshots can be deleted. But you should think about backups instead of snapshots. Snapshots use expensive high-speed storage, while you can keep backups on dedicated server with a bunch of BIG and cheap SATA drives, or even on magnetic tape.

>3. Regarding Backups, what are the differences between snapshots and backups (data recovery tool)?

Backups are VM copies on another media. Snapshot is recorded state of VM you can quickly revert to.

>4. If I'm planning to backup servers (data recovery tool) over the network, will it extremely load it?

Not more load than on standard file server.

>1. Is the delta taken from the original state or from the last snapshot?

Delta is a difference to last active snapshot. There can be even a tree of snaphots, not always just a line.

>2. Do I need to take the snapshots after deleting the previous one or I can take snapshot and then delete the previous one?

You can just delete snapshot without taking new. Most my VMs do not have any snapshots.

>3. Is it possible that one snapshot will be bigger than the hard drive of the VM?

Maximum size of snapshot is sum of all hard drives plus VM RAM size.

>4. So if I'm using VDR I'll get a complete machine for every backup, right? Isn't it too "heavy" for the network (the backup is done on remote FTP)?

You should know better your network and available bandwidth.

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VMware vExpert '2009

http://blog.vadmin.ru

[vAdmin]

Hi All,

Is there any hard limit of how big is the RDM partition size that can be backup using VDR ?

Thanks.

Kind Regards,

AWT

[AntonVZhbankov]

I suppose there is no such limitations. VDR can backup any VM and maximum size for both VMDK and RDM disks is 2TB.

But I strongly do not recommend VDR to backup such VMs. Backup system disk / partition only with VDR and backup data with traditional backup solutions.

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MCSA, MCTS, VCP, VMware vExpert '2009

http://blog.vadmin.ru

[ShaneWendel]

vDR is actually a virtual appliance that mounts each VMs VMDK Files. Since it uses deduplication, theoretically, each backup should take a shorter amount of time depending on how much the data has changed. vDR does not use FTP, it can use local storage as a VMDK, an RDM or a CIFS share as a backup target.

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Shane Wendel, VCP