I heard that if you have a big snapshot to delete (keep the modifications) you should take a small snapshot again and then "delete all" so that the consolidation takes place in background.

Is it a good way to manage big snapshots?

  • How big are you talking? – ewwhite Feb 16 '18 at 16:50
  • That's a good question. I don't have yet a concret example. – Pozinux Feb 16 '18 at 16:59

There is a really interesting article about performing safe removal of large snapshots on VMware. All credits goes to Ideen Jahanshahiand and his great blog post. Screenshots have been replaced on request by @Gerald Schneider.

TLDR of the article;

Why Take Precautions

Although snapshot removal has been substantially improved in ESXi 5.0 and ESXi 5.1, it is still possible for a virtual machine to appear something similar to a suspended state. See http://kb.vmware.com/kb/1031106 regarding ESX/ESXi 4.1. For a business critical application such as Microsoft Exchange that must remain active, this can have devastating effects as the snapshot removal process cannot be cancelled once it has been initiated.

Removing a Large Snapshot

Although it can be labor intensive, a common way of removing a large snapshot is to take a new snapshot. This will add a degree of separation from the base image to the child.

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In the example below, Snapshot the Virtual machine’s memory has been unchecked and the Snapshot was named Safe Snapshot Removal. By unchecking the box shown below, this will assist in removing the “Safe Snapshot” once the other snapshot was removed.

enter image description here

With the current example, there are now 2 existing snapshots.

enter image description here

Next, remove the large “pre-install” snapshot. This will roll this snapshot back into the parent and will no longer cause any downtime. Note that this can potentially cause greater I/O penalties, so calculate the risks before proceeding with this method.

enter image description here

Once the pre-install snapshot has been deleted, I do a quick check to verify that the Safe-Snapshot Removal snapshot is fairly small. If no, repeat the process. If yes, the Safe-Snapshot Removal snapshot can be deleted.

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    Whilst this may theoretically answer the question, it would be preferable to include the essential parts of the answer here, and provide the link for reference. – Gerald Schneider Feb 19 '18 at 7:05
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    @GeraldSchneider I've added the part that explain how to safely remove big snapshot. – Tolsadus Feb 20 '18 at 8:53
  • While this is now a really great answer it would be even better if you had created your own screenshots instead of ripping the images from that "great article" and violating the copyright of the author. – Gerald Schneider Feb 21 '18 at 14:51
  • Done @GeraldSchneider ;) – Tolsadus Feb 21 '18 at 15:12
  • Great ... just one last thing (sorry for nitpicking): in your screenshot for taking the temporary snapshot you have the checkbox for the guest memory checked, but it should be unchecked (you write it correctly in the text). If you fix that you have a perfect answer ... I'd upvote it again if I could. – Gerald Schneider Feb 22 '18 at 7:01

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