Go Premium for a chance to win a PS4. Enter to Win

x
?
Solved

VMWare 4/Netapp: When you delete a VM snapshot..

Posted on 2012-03-19
5
Medium Priority
?
686 Views
Last Modified: 2012-03-19
When you delete a VM snapshot (we are on VMWare 4 and have Netapp iscsi storage) - is that a write intensive operation?  Or is it just a matter of removing a pointer?
0
Comment
Question by:amigan_99
5 Comments
 
LVL 124

Accepted Solution

by:
Andrew Hancock (VMware vExpert / EE MVE^2) earned 2000 total points
ID: 37738349
It can be Read and Write Intensive as it merges the snapshot to the parent disk.

It's not the same as a NetApp Filer Snapshot.

A snapshot is NOT a backup of a VM; that is a gross misconception.  

A snap shot is a way to preserve a point in time when the VM was running OK before making changes. A snapshot is NOT a way to get a static copy of a VM before making changes.  When you take a snapshot of a VM what happens is that a delta file gets created and the original VMDK file gets converted to a Read-Only file.  There is an active link between the original VMDK file and the new delta file.  Anything that gets written to the VM actually gets written to the delta file.   The correct way to use a snapshot is when you want to make some change to a VM like adding a new app or a patch; something that might damage the guest OS. After you apply the patch or make the change and it’s stable, you should really go into snapshot manager and delete the snapshot which will commit the changes to the original VM, delete the snap, and make the VMDK file RW. The official stance is that you really shouldn’t have more than one snap at a time and that you should not leave them out there for long periods of time. Adding more snaps and leaving them there a long time degrades the performance of the VM.  If the patch or whatever goes badly or for some reason you need to get back to the original unmodified VM, that’s possible as well.  

I highly recommend reading these 2 articles on VMware Virtual Machine Snapshots:

Understanding Snapshots - http://kb.vmware.com/kb/1015180
Snaphot Best Practices - http://kb.vmware.com/kb/1025279

Also check out the following Snapshot Articles by Eric Siebert

Pt.1- http://is.gd/Lajg4p
Pt.2- http://is.gd/NdKQWC
Pt.3- http://is.gd/tp2vEK
0
 
LVL 10

Expert Comment

by:Alan_White
ID: 37738368
It would depent.

Typically when you take a snaphot, the original vmdk is frozen and all changes are written to a newly created snapshot file.

When you come to delete it, typically you want to commit the changes (made since the snapshot was taken) back into the vmdk.  Therefore this is write intensive.

If on the other hand you want to roll back to the snapshot and then delete the "forward" changes, it will be less write intensive.
0
 
LVL 124
ID: 37738371
Depending upon the size of the snapshot, how many snapshots, how long VM has been running on a delta (snapshot) disk, how fast the datastore, SATA or SAS disks, RAID type, it could take many hours, to the longest I've seen 4 days to merge the disks.
0
 
LVL 42

Expert Comment

by:Paul Solovyovsky
ID: 37738538
I concur with @hanccocka, don't get your vmware and Netapp snapshots confused.  

SMVI can do both (while making a backup so it can quiesce the VM using vmware snapshots prior to taking Netapp snapshots)  The load and read/write is minimal since it's only for a short period of time.
0
 
LVL 1

Author Closing Comment

by:amigan_99
ID: 37738576
This answer is so awesome I wish I could give more points!  Thank you.
0

Featured Post

Concerto Cloud for Software Providers & ISVs

Can Concerto Cloud Services help you focus on evolving your application offerings, while delivering the best cloud experience to your customers? From DevOps to revenue models and customer support, the answer is yes!

Learn how Concerto can help you.

Question has a verified solution.

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

A look at what happened in the Verizon cloud breach.
August and September have been big months for VMware—from VMworld last month to our new Course of the Month in VMware Professional - Data Center Virtualization. We reached out to Andrew Hancock, resident VMware vExpert, to have a more in-depth discu…
This tutorial will walk an individual through setting the global and backup job media overwrite and protection periods in Backup Exec 2012. Log onto the Backup Exec Central Administration Server. Examine the services. If all or most of them are stop…
How to Install VMware Tools in Red Hat Enterprise Linux 6.4 (RHEL 6.4) Step-by-Step Tutorial

971 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