ZFS Usage Inconsistency

[syphant]

Unraid GUI says I am using 46.1 TB of my ZFS pool and that I only have 17.7 TB free, so I went to take a look at what I can get rid of to free up some space. But when I use QDirStat to try to find what is taking up so much space, it says I am only using 23.1 TB? What gives? Any ideas what I can do to see what is using up all this space and/or why QDirStat is reporting a lower amount of usage?

[syphant]

Ran NCDU for good measure and it is also reporting 23.1 TB usage just like QDirStat is.


Also attached syslog and diag:

acidbath-syslog-20230813-1655.zipacidbath-diagnostics-20230813-1256.zip

[HuHa]

For one thing, QDirStat explicitly tells you ">23.1 TB", i.e. MORE THAN 23.1 TB because it could not read all directories below /data/appdata, probably because of insufficient permissions. The part of the screenshot that was cut off (below the tree) also notified you of that.

 

But even then there will probably be a mismatch because of ZFS snapshots which, like Btrfs snapshots, also are not reported by ZFS to the relevant system calls like stat(). You will need dedicated ZFS tools to give you that information.

 

HTH

HuHa

QDirStat author

[syphant]

9 minutes ago, HuHa said:

For one thing, QDirStat explicitly tells you ">23.1 TB", i.e. MORE THAN 23.1 TB because it could not read all directories below /data/appdata, probably because of insufficient permissions. The part of the screenshot that was cut off (below the tree) also notified you of that.

 

But even then there will probably be a mismatch because of ZFS snapshots which, like Btrfs snapshots, also are not reported by ZFS to the relevant system calls like stat(). You will need dedicated ZFS tools to give you that information.

 

HTH

HuHa

QDirStat author

 

The appdata directory is located on my cache drive and not on my ZFS array so that is not related. Sorry I neglected to state that in my original post!
However, I did try rebooting the server and now the Unraid GUI is showing I only 25.4 TB usage of my ZFS pool whereas it was showing 46.1 TB before the reboot, which is very interesting, but still not the same as what QDirStat and NCDU are both reporting (23.1 TB)

[Kilrah]

5 minutes ago, syphant said:

but still not the same as what QDirStat and NCDU are both reporting (23.1 TB)

TB vs TiB again.

 

 

[syphant]

7 minutes ago, Kilrah said:

TB vs TiB again.

 

 

Ahh you're correct, so a reboot did fix the issue. Thanks!