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This is ESXi 5.5.

I know that the VMWare KB is very against long running snapshots, however I do not know of another way to do this.

Let's say I have a base Linux system and want to spin up a unique VM for each user. I could simply snapshot the system and give it to the user. If the user messes it up or needs a refresh I could simply delete the snapshot and create a new one.

I am aware of VMWare templates however let's say my base image is 10GB. That mean each user's footprint will be (say 5 users):

  • 10GB (base) + ~1GB for user files
  • 10GB (base) + ~1GB for user files
  • 10GB (base) + ~1GB for user files
  • 10GB (base) + ~1GB for user files
  • 10GB (base) + ~1GB for user files

55 GB

If my understanding is correct, the snapshots only store the DIFFs between the base so that would give:

  • 10GB Base
  • ~1.1GB for user files, log updates, etc.
  • ~1.1GB for user files, log updates, etc.
  • ~1.1GB for user files, log updates, etc.
  • ~1.1GB for user files, log updates, etc.
  • ~1.1GB for user files, log updates, etc.

15.5GB

The snapshot solution seems so elegant and such an efficient use of space where as templating is so redundant.

Are long running snap-shots really that bad and is there a better way to accomplish this?

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  • 1
    is there a better way to accomplish this? - A storage system (e.g. SAN) that supports de-duplication would deal with this just fine.
    – Zoredache
    Nov 5, 2014 at 23:14
  • Which is essentially the same thing as snapshots right? It's a differential file system just implemented better than VMWare's version?
    – jladsfaljsdfjladsf
    Nov 5, 2014 at 23:18
  • 2
    No, deduplication and snapshots are very different things. Deduplication can find duplicate areas (e.g. common OS files) on many different VM images.
    – Sven
    Nov 5, 2014 at 23:21
  • @SvW - So de-dupe can be thought of as on-the-fly compression. i.e. block 1102304, 234823489, 29348234, and 9283493 are exactly the same, so just put a pointer to 1102304 in all the other blocks and if a few bytes within them change just track the diffs
    – jladsfaljsdfjladsf
    Nov 5, 2014 at 23:41
  • YES, they are that bad. Use templates to make new VMs for users.
    – mdpc
    Nov 6, 2014 at 0:11

1 Answer 1

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3

There's a feature called linked clones, that's possibly what you're looking for. I think it's baked into ESXi but you can't use it without an additional component. VMware wants you to have View, vCloud Director or vCloud Automation Center (renamed to vRealize Automation); they all support linked clones afaik.

There are ways to do it but they are unofficial and unsupported. For example: How to create linked clone on the vcenter?

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