Transfers from multiple windows clients repeatedly fail with a "There is not enough space on the disk." 

windows side:

1. Failures from windows explorer / Xcopy no difference
2. "Retry" can be pressed multiple times and will restart, then fail
3. No other access / permission issues 
4. 10GBE NIC's on clients
5. pinging no issue  Reply from 10.1.1.93: bytes=32 time<1ms TTL=64

Unraid side:

1. No log entries generated (is there a way to increase logging level?)
2. Target share (/data) has 70 TB free
3. Errors seen with SMB settings "Enhanced Mac ON/Off"  (currently OFF)
4. Errors seen with SMB settings "SMB MultiChannel ON/Off"  (currently ON)
5. 10 GBE on Unraid eth

 

I've been testing (fiddling) with the share's use of cache pool; - was 'yes' but when I change to 'no' - it seems to be not be failing, but really need re-enable for performance.   FWIW, share (data) cache (hdd) is 3*14 TB btrfs raid0, as trying to transfer 100 TB into array.

 

 

 

There is not enough space on the disk.

tower-diagnostics-20230329-2014.zip

Edited March 30, 20233 yr by schreibman
add

sorry for the dupe post.   i also posted in general

You must set the minimum free space for the share, it should be set to twice the largest file you expect to transfer, or when cache is full (and later arrays disk) it will fail.

18 hours ago, JorgeB said:

You must set the minimum free space for the share, it should be set to twice the largest file you expect to transfer, or when cache is full (and later arrays disk) it will fail.

THANKS!  (... aaand it was right there on the screeen as well "

Choose a value which is equal or greater than the biggest single file size you intend to copy to the share. Include units KB, MB, GB and TB as appropriate, e.g. 10MB.

"

10 hours ago, schreibman said:

THANKS!  (... aaand it was right there on the screeen as well "

Choose a value which is equal or greater than the biggest single file size you intend to copy to the share. Include units KB, MB, GB and TB as appropriate, e.g. 10MB.

"

Note that if you later set up the share to use a pool for caching purposes the pools have their own Minimum Free Space setting.

On 3/31/2023 at 6:55 AM, itimpi said:

Note that if you later set up the share to use a pool for caching purposes the pools have their own Minimum Free Space setting.

Good call out.   Assume that:  Is this correct? :

[Share Minimum Free Space setting] = [Share Minimum Free Space setting] = [2 * Largest File Size]

1 hour ago, schreibman said:

Good call out.   Assume that:  Is this correct? :

[Share Minimum Free Space setting] = [Share Minimum Free Space setting] = [2 * Largest File Size]

Strictly speaking the value should be "at least the Largest File Size" + safety margin.  Using 2x gives a safety margin as drives getting completely full is a bad idea as it might cause file system corruption, and also if you ever need to run File System repair some work space is needed.

Hi,

I have the same problem by trying to use the "Backup and restore (Windows 7)" function. The backup runs and it seems almost to be finished but then I get the error due mssing space. I have created a separate pool for backups - 1.5 TB disk space - so plenty enough to backup my home folder from Windows.

I already retried the backup and also completely restarted from scratch (deleted the backup from the unRAID backup pool) but no luck. What ist the matter with the "Minimum free space"? On my pool it was predefined to 146.5 GB and I cannot even set it to zero:

Does this option really matter or is the failure caused by something else. I am a bit confused and have no idea. Can somebody help, please?

Please post the diagnostics.

2 hours ago, JorgeB said:

Please post the diagnostics.

Hi, I attach the diagnostics as Zip file.

tower-diagnostics-20250914-1310.zip

3 hours ago, cup089 said:

What ist the matter with the "Minimum free space"? On my pool it was predefined to 146.5 GB and I cannot even set it to zero:

If you try to reset it to zero then Unraid will automatically set it to a value based on % of disk size. You can set it to a very small non-zero value to avoid this.

However it seems unlikely that value is relevant unless you were filling up the drive enough to get to that limit.

Share looks fine. Is the problem only with Windows Backup, i.e., if you copy files directly to that share, does it work?

1 hour ago, JorgeB said:

Share looks fine. Is the problem only with Windows Backup, i.e., if you copy files directly to that share, does it work?

Yeah copying to this particular share manually is working without any issues.

Edit: Okay I just disabled the option to include a system recovery disk (actually do not know how its called in English) and after that the backup runs without any issues.

Edited September 14, 2025Sep 14 by cup089