Min Free Space not working with High Water?

[johnsanc]

I have an issue where one of my drives keeps filling up. It looks like the min free space setting is not being obeyed. Anyone know what I'm doing wrong or is this a bug?

I also confirmed that there are directories on most other disks that it could write to, but for some reason its prioritizing disk 14 which doesn't have enough space for the largest files I would be writing.

Note: As you can see from the screenshot, everything is pretty balanced except disk 14. The only change I made recently was upgrading to 6.12.11 from 6.12.9 a few days ago. Diagnostics attached.

Edit: Based on the description of High Water: "Choose the lowest numbered disk with free space still above the current high water mark. The high water mark is initialized with the size of the largest Data disk divided by 2. If no disk has free space above the current high water mark, divide the high water mark by 2 and choose again."

So that would mean...
18 / 2 = 9 TiB
9 / 2 = 4.5 TiB
4.5 / 2 = 2.25 TiB

2.25 / 2 = 1.125 TiB (currently here)

 

Ok so its filling up the lowest numbered disk that had at least 1.125 TiB of free space... but then what? I can see its writing to both disk 14 and disk 15, but I would NOT expect any writes to disk 14 since its has far below the min free space.

 

tower-diagnostics-20240731-1344.zip

Edited July 31 by johnsanc

[JorgeB]

Make sure you are not overwriting existing files, those would go to the disk were they exist.

[johnsanc]

Nope thats not the case, these are all brand new files.

[JorgeB]

I'm not aware of any bugs with this, but it's always a possibility, stop any array writes, type:

 

touch /mnt/user/games/a

 

and then confirm on which disk that got created, and post the diags right after that

[johnsanc]

Written to disk 15 which is correct.
I think I see what the issue is though... during a very large transfer, a ton of temp files were created before their full filesize was allocated. So most of the temp files were written to disk 14 initially then grew as the transfer was going. So yes what you originally said was correct, but I guess I should always pre-allocate disk space to avoid this issue.

[johnsanc]

Well this is interesting... I am transferring some of the temp files manually from disk 14 to disk 16 and I can see in midnight commander I have transferred over 100 GiB so far, but the unraid UI only has disk usage decreased by about 10 GiB... I opened some of the files in a hex editor and confirmed they are mostly zeroes.
 

I would have expected the disk usage to decrease, but it sounds like unraid's disk space calculation is NOT including the zeroed space of sparse files.

Edit: Yeah this is a problem... This is only an 8 TB disk but it says 9+ TB occupied. Apparently committed sparse space is NOT considered in unraids calculations for free space. IMO, unraid's disk allocations should be changed to use the space metrics as shown here since it’s more impactful for allocation purposes than whatever is shown on the main page. @JorgeB - Welcome your thoughts on this one!

Edited August 1 by johnsanc