Not enough space but I still have 2TB available.

[danielebiancoxch]

 

Hello and sorry for my bad English. I have a problem with a share in a disk pool. The share is 108 TB and there are still 2.22 free but if I try to copy into it it tells me that the space is full. I've already tried balancing and scrubbing without any success, and trying some settings.

 

 

 

 

I leave you the diagnostic file attached. Thank you

tower-diagnostics-20230911-1944.zip

[JorgeB]

The pool is fully allocated and there's no more space for a new metadata chunk, this can happen with btrfs, there's a little trick you can do to get around it but you'd first need to move some data out of the pool, I can post more details if interested.

[danielebiancoxch]

Hi Jorge, thanks for the reply. Yes, I would be very interested, I would like to recover the 2Tb of space. Do you already know how much data I will have to move? the operation does not lead to data loss, does it? Thank you

[JorgeB]

21 minutes ago, danielebiancoxch said:

Do you already know how much data I will have to move?

Usually 50/60GB is enough, you just need to free up some unallocated space, large files will be best, you can check yourself then to see if it's enough, type 

btrfs usage -T /mnt/plot_share

 

Id Path      single   DUP       DUP      Unallocated Total    Slack   
-- --------- -------- --------- -------- ----------- -------- --------
 1 /dev/sdf1 16.33TiB  36.00GiB 64.00MiB     1.01MiB 16.37TiB  3.50KiB
 2 /dev/sdh1 16.34TiB  27.00GiB        -     1.01MiB 16.37TiB  3.50KiB
 3 /dev/sdi1 16.33TiB  40.02GiB        -     1.01MiB 16.37TiB  3.50KiB
 4 /dev/sdg1 16.33TiB  36.00GiB        -     1.01MiB 16.37TiB  3.50KiB
 5 /dev/sde1 16.34TiB  32.00GiB        -     1.01MiB 16.37TiB  3.50KiB
 6 /dev/sdd1 16.33TiB  38.00GiB        -     1.01MiB 16.37TiB  3.50KiB
-- --------- -------- --------- -------- ----------- -------- --------
   Total     98.02TiB 104.51GiB 32.00MiB     6.07MiB 98.23TiB 21.00KiB
   Used      96.01TiB 104.00GiB 10.22MiB                              

 

Note the Unallocated column, it needs at least a couple of GBs, post that when it's done.

[danielebiancoxch]

Ok I'm freeing up 200GB of space. I tried running the command but it says:

 

 

Am I doing something wrong?

[JorgeB]

Sorry, my mistake, should be:

btrfs fi usage -T /mnt/plot_share

 

[danielebiancoxch]

Now It works:

[JorgeB]

OK, now create a temp folder inside /mnt/plot_share, cd into it and type:

 

dd if=/dev/urandom bs=1024 count=1050000 | split -a 6 -b 2k - file.

 

This will create many small files in that folder to force allocate some metadata chunks, once complete start copying data normally again, when the fs is close to full remove that temp folder.

[danielebiancoxch]

Ok, but the comand not work.

[JorgeB]

Command is incomplete, copy/paste from the one above

[danielebiancoxch]

Ah sorry, something went wrong in the copy paste.

Thank you very much anyway, it works perfectly. I had to repeat the operation a couple of times to be able to use the remaining space. But now Windows tells me that I still have XXX space available but I don't understand how it calculates it.

 

 

 

Is this normal or do you have some other trick?

 

Thanks again for your kindness.

[JorgeB]

1 minute ago, danielebiancoxch said:

Is this normal

Now it's really full, there are only 35GB free, Windows is not showing the correct stats, they can differ a little.

[danielebiancoxch]

Perfect.

Thanks again and good work.