How to check if a Zvol is Sparse thru Freenas

[wreedps]

How do I check an existing zvol is Sparse thru the FreeNAS GUI or CLI?

 

[Mirfster]

Would this help?

http://cuddletech.com/?p=16

Others may have a faster/better way; but I am a noob... :D

 

[wreedps]

Hmm when I do zfs get reservation, volsize even on a non sparse volume it does not show it to have a reservation. I am trying to find out a way to easily tell if the zvols are sparse volumes.

 

[Mirfster]

Here is what I did on a test box (I guess I should have done it on my Test VM... lol)

Have some items as shown (was mucking around with TFTP..):

"BigSparseZVol", I set to 500GiB (even though that is more than capable). Was testing so no harm; no foul.

Anyways, I think the property you may be looking for is "refreservation"; since to me that is the different Property/Value between them

My command: zfs get refreservation,volsize TFTPVolume/SparseZVol TFTPVolume/BigSparseZVol TFTPVolume/NonSparseZVol

Results:

Looks like the sparse volumes have "none" for "refreservation".

Of course I could be 100% wrong too..

If you want, you can run the command using "zfs get all" for the volumes and you will see all the different Properties/Values.

 

[wreedps]

Hmm I did the same thing, but I was looking at reservation, not refreservation! Let me try again myself

 

[wreedps]

Perfect I see now, I am good, thank you!

 

[Mirfster]

NP, glad to help where I can.