Possibly abandoned volume, using extra space

[Cliff Steinman]

I have one volume (mimsy, 369.8 GiB used) with one dataset (mimsy, 247.3 GiB), two zvols (files, 246.2 GiB|witness, 1.0 GiB). I'm presenting them as an iSCSI device to Hyper-V. You may have noticed my volume is taking up much more than the data it lists. I believe this may be due to an abandoned dataset, replication, or iSCSI file extent. However, an ls -la on /mimsy only shows md_size and mimsy. Within, only files and witness. Since the zvols are being presented as a device I'm not seeing anything under files.

First question: is there a way I can see the data stored within the zvol, I know a file extent would create a .extent file in there?

Second question: how do I find the 122.5 GB that the volume shows, but the contained datasets don't contain?

For reference, my volume screen looks like:
Name Used Available
mimsy 369.8 GiB (53%) 322.2 GiB
-----mimsy 247.3 GiB (55%) 199.2 GiB
--------files 246.2 GiB (55%) 199.2 GiB
--------witness 1.0 GiB (0%) 200.2 GiB

 

[HoneyBadger]

The "volume" level shows the raw disk total before parity overhead, dataset will show after parity.

I'm guessing this is a RAIDZ volume?

 

[Cliff Steinman]

That's correct, z1. But I'm looking at someone else's pool that's looking like I'd expect, same sizes, that is z1. Also, my volume's used and available add up to 700GB. Except my vdev is 3 x 250GB. With your information, the primary dataset would then be out of 500GB, except 248 used + 198 avail = 446 total. Which is much smaller.

 

[nojohnny101]

post a screenshot of your "storage tab". I think the question you are asking deals with lost space due to parity and other space that FreeNAS uses to do its magic.

Just to be sure though, show us exact numbers and layout of your storage.

EDIT: also do you use snapshots?

 

[Jurgen Segaert]

The number that shows in the topline of "Volume" may or may not include parity (depends on the FreeNAS release) and has been a source for confusion.
Can you please post the output of the following command?

Code:

zfs list -o name,used,refer,usedsnap,avail,mountpoint -d 1

 

[danb35]

The number that shows in the topline of "Volume" may or may not include parity (depends on the FreeNAS release)

The fact that it's showing the root dataset indicates that he's on 9.3 or newer. Previous versions hid that dataset (it was always there; that's something inherent to ZFS), and yes, the change in 9.3 has been a source of considerable confusion. The manual now has some explanation, at least.

@Cliff Steinman, your problem is exactly what @HoneyBadger stated--snapshots have nothing to do with it. I can speak to what you've seen on other systems, but if you can give us detailed examples we might be able to go from there.