Volume Used Space

[robsonj]

Hi There,

I have set up my FreeNas box, and its been running quite well. But on the UI I noticed a large descrepency between what the UI claims my volume has for used space and what a shell 'df -h' reports.

From the command line df -h reports the following for my volume...

Filesystem Size Used Avail Capacity Mounted on
tank/Photos 1.0T 616G 424G 59% /mnt/tank/Photos

But the UI shows used of 984.5Gb.

Anyone know what the reason is for this? Is there some cleanup script I need to run as I have been doing a lot of copies to the volume etc.

I'm wondering if the UI is reporting the df -h 'Size' column as the used value? Though I'm not quite sure how the dataset has a size of 1TB.

Thanks for any help!

Cheers
Jonathan

 

[danb35]

No, the GUI isn't using the result of df to report capacities (it's parsing 'zfs list' instead), and df is known to give unreliable information with ZFS (due to compression, snapshots, deduplication, etc.).

Can you post a screen shot of the storage screen in your web GUI?

 

[robsonj]

Yea. I guess df is only an estimate, but in this case the figure its producing is far closer to what I'd expect, here is a screen shot. As you can see it does all add up within itself (except the total Available). Interestingly I had a file on the torrents dataset which accounted for the 600+mb of space used. I just delete it but the used space remained the same. So I'm wondering if there is some zfs task that periodically updates the stats or something?


Thanks for the help!

Cheers
Jonathan

 

[depasseg]

"zfs list -o space" will show you a per dataset list of the space utilization, including snapshots, which is what I'm guessing is the culprit.

 

[danb35]

There isn't a ZFS task to automatically update the stats. Do you have snapshots enabled? They can result in unexpected capacity reports.

 

[depasseg]

The usage stats refresh every time you view the storage volume status page. To refresh, I just click to a different screen and then click "storage".

 

[robsonj]

Thanks guys, I bet its snapshots as there have been a lot of files changing as I populate the dataset. I bet thats it!

 

[robsonj]

Yep, thats it 85 6.7Gb snapshots! Thanks again all for the help!