High cache usage (out by around 200gb)

[vcxpz]

I have a cache array of 3 500gb drives gaining me 750gb usable cache usage. but apparently I've used 251gb but there's nothing on the cache. I know that last week it said 3 gb used which is around correct. nothing happened in between now and then that I know of.

Running 6.9.0-beta25

 

Anyone know why its saying I've used 200gb?

skynet-diagnostics-20200720-2131.zip

[JorgeB]

There was a recent change on how free space is reported with btrfs, unfortunately it doesn't appear to work correctly for a 3 device raid1 pool, I wonder if df reports correctly, please post the output of:

 

df -hH | grep cache

 

[vcxpz]

15 minutes ago, johnnie.black said:

There was a recent change on how free space is reported with btrfs, unfortunately it doesn't appear to work correctly for a 3 device raid1 pool, I wonder if df reports correctly, please post the output of:

 

df -hH | grep cache

 

 

[JorgeB]

Yep, df is also reporting the wrong free space, so it's a btrfs issue, df does report the correct used space unlike Unraid, but that's a known issue, since it currently calculates the used space by subtracting free space from total capacity.

[vcxpz]

2 minutes ago, johnnie.black said:

Yep, df is also reporting the wrong free space, so it's a btrfs issue, df does report the correct used space unlike Unraid, but that's a known issue, since it currently calculates the used space by subtracting free space from total capacity.

So this is a bug? Should I be worried about it? Or should I ignore it until it’s been patched? (Assuming it’ll be patched in the next update)

[JorgeB]

Just now, vcxpz said:

So this is a bug?

Wrong free space is a btrfs bug, wrong used space is an Unraid bug, so you'd need to wait for a newer kernel that includes a btfs fix, the wrong used space in some cases is already a known issue and should be fixed in a future Unraid release.

 

You can always see the correct stats by typing on the console:

 

btrfs fi usage -T /mnt/cache