Delete large snapshots

[lume001]

Hi everybody,

I would like to get some conformation or help, that I can delete two large snapshots that I made. Both are about 500 GB size. The problem is that this is mail server and I can't just play with it (power on, power off). The first shapshot was made before mail software version upgrade and the second snapshot was taken before adding second disk 100 GB to VM and then LVM resized(I've read that this is a big issue; disk resize and snapshots). I believe there is also performace issue because of snapshots and in later time also storage space problems will occur.

I would appreciate any help before things go wrong,

Luka

[valgubelli]

first delete 1st took snapshot and than go for second one. after you delete both snapshot do the VM consolidation.

due to large size it will take long time to get Snapshot delete. you have to wait till it completes.

[lume001]

Thanks for reply,

would you suggest to delete snapshots when VM is running (live)? Can you give any information in your case, mostly I am concerned about times. I can't calculate how long it would take to delete both snapshots and consolidate disks on VM. Will it take more than 48 hours. Host has 10k SAS disks in RAID5.

Thanks.

[valgubelli]

It depends on storage speed. you can delete Live. No issues.

it may take time 30-40 Hours. don't cancel task in middle of snapshot deletion

[Devi94]

I had 2TB size of snapshot in production environment. I did snapshot deletion when VM is online. it took me around 5 hours.

[lume001]

What about 2nd snapshot I mentioned (added disk to VM and LVM resize in OS). Can I expect worst case scenarios. I can't even backup or clone the VM, because all 3rd party tools (etc. Veeam) don't support ESXi free.

[Devi94]

Basically when you are deleting snapshot it will commit all your changes to base disk. So nothing will go wrong. Only thing is you need to be patience until the activity is completed. Remove snapshots after business hours.

[wila]

Hi,

Be aware that you need sufficient free storage space on the LUN that your VM lives in order to commit the snapshot(s).

The amount of free space is required is roughly:

- size of disk(s) which has the snapshot(s)  plus

- size of the snapshot plus

- several GB of buffer, rule of thumb would advise it to be > 20GB

The required buffer depends on things like how active your VM is. While merging the snapshots and your VM is in a running state, it will create a new worker snapshot where all the current activity is saved. So if your VM is very busy writing then you best have extra space free.

You'll need a few GB extra anyways as headways for other things that can happen, like powering on a VM at the same LUN that then has to write out its memory backed file (eg. size of the RAM)

--

Wil

[lume001]

Thanks for anwsers. I'll give it a try on weekend. I'll report on results.

---

Luka

[lume001]

Hello,

it took just 4 hours for both snapshots. Very Good.

Nice day to everyone,

Luka

[MFenton120467]

Hey Wila, I have a question about your size comment, I have a vm on a 15TB datastore, Ihave a 2.5Tb snapshot I want to delete, there is 10TB remaining on the Datastore is this going to be enough?

[Finikiez]

Hello!

If you start deleting snapshot you can't cancel the task until it's finished.

And if you get performance issues during that time you will have to wait and feel the pain :smileyhappy:

I recommend to schedule a downtime or plan to delete snapshots during off-business hours.