Solved

Hyper-V snapshots

Posted on 2015-02-18
3
173 Views
Last Modified: 2015-02-27
Before doing some work on a Hyper-V VM, I want to make sure I can reverse the change should something happens. I know this can be done with snapshot but I wonder if they are really worth it. The .AVHD file can occupy a significant amount of space and it won't give it back until the VM is restarted. Also, the merging process makes me nervous.  Sometimes I find it easier to just shutdown the machine, copy the .VHD file, restart the VM, do the work on it and if nothing bad happens, I simply delete the copy after a few days. Am I causing an unnecessary headache by proceeding like this? The Hyper-V host runs on W2k8 R2.


Thank you!
0
Comment
Question by:Alan Dala
  • 2
3 Comments
 
LVL 58

Accepted Solution

by:
Cliff Galiher earned 500 total points
ID: 40617939
It really depends on the workload. Taking a checkpoint *or* putting an old VHD back in place for a DC, as an example, would have equally bad consequences.

Checkpoints tend to be faster, and if you have large AVHDs, that's usually a good sign that you are letting them linger too long. Having a checkpoint around for weeks is terrible for performance, but replacing a VHD with a two-week old copy would be equally as bad for *most* workloads.

In short, checkpoints are not intended to replace real backups, but do make a nice supplemental tool for quick low-risk maintenance tasks and *don't* require taking the VM offline for an extended period, unlike copying a VHD. I use them regularly and safely for things like monthly patches, minor app changes, or other things that a quick rollback would be nicer than a full BMR should the task go sideways. But they don't linger beyond 48 hours. Ever.
0
 

Author Comment

by:Alan Dala
ID: 40636593
Hi and thank you for your answer.

Patches are the reasons why I'm looking into using 'snapshots'. The problem is that my VMs run on W2k8 R2  so there is no 'live' option to  consolidate snapshots. The idea of turning off the servers in order for the snapshots to consolidate, it's a real concern. It doesn't seem to work when you 'shut down'. It needs a hard shutdown which is not ideal to say the least. It looks like 2012 has the ability to consolidate snapshots while live but I'm still not sure of what's going on in the background. Is the performance affected in any way? Is this transparent to the users?


Thank you!
0
 
LVL 58

Expert Comment

by:Cliff Galiher
ID: 40636606
Yes, you need yo shut down the VM to merge in 2008 R2. That would be the reason I said you don't need to shut down "for an extended period" as copying a VHD requires. I didn't say the maintenance window was zero.

You should not have to "hard" turn off a VM though. Shutting down works. If it isn't, you have some other problem.

Yes, 2012 supports live merges.

Yes, there is a performance penalty during the merge.

So yes, that means end users may notice the performance slowdown during the merge.

As I said, this isn't a replacement for backups, nor does it replace proper maintenance planning in regards to staff communications, maintenance windows, and finding times of least impact.
0

Featured Post

Optimizing Cloud Backup for Low Bandwidth

With cloud storage prices going down a growing number of SMBs start to use it for backup storage. Unfortunately, business data volume rarely fits the average Internet speed. This article provides an overview of main Internet speed challenges and reveals backup best practices.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Windows 2012 R2 - Backing Up Server 3 59
AD Account lockout 11 62
Blocking Microsoft Edge From Running? 14 54
NTP time source for DC 3 41
OfficeMate Freezes on login or does not load after login credentials are input.
Is your company's data protection keeping pace with virtualization? Here are 7 dynamic ways to adapt to rapid breakthroughs in technology.
This tutorial will show how to configure a new Backup Exec 2012 server and move an existing database to that server with the use of the BEUtility. Install Backup Exec 2012 on the new server and apply all of the latest hotfixes and service packs. The…
This tutorial will show how to configure a single USB drive with a separate folder for each day of the week. This will allow each of the backups to be kept separate preventing the previous day’s backup from being overwritten. The USB drive must be s…

713 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question