I would like to backup a NAS that has image files  some of which are 5tb in size to an Unraid share.  Unraid capacity is 80tb and is a mix of 4, 6 and 8 tb drives.  Plan on using reconstruct write and writing directly to array (not using cache drive),  My question is what the "Minimum free space" setting should be?  I think it has to be larger than the biggest file expected but wished to clarify.  Feedback appreciated.

 

3 hours ago, rwilkers said:

My question is what the "Minimum free space" setting should be?  I think it has to be larger than the biggest file expected but wished to clarify.

Yes........  BUT subject to the restriction in the first paragraph of this section:

 

          https://docs.unraid.net/unraid-os/manual/shares/user-shares/#minimum-free-space

 

You should be fine with 'Split level' you currently have!

Note that Unraid does not split files across drives so to copy files of the size you mention you have to have that much free space on the target drive before starting the copy.

Also google    TiB vs TB     as there is big, big difference the size of these two ways of measuring a 'terrabyte' and folks have been noted to be fast and loose when it suits them.  Plus, the numerical difference is much smaller say at KiB(1024) v KB(1000).

Thank you for the the information, I appreciate your courtesy in replying.  I tested this and found what I *think* is an anomaly but I will do further checking and then reach out when I am sure of my facts.   In the testing with 5.3Tb set for the "Minimum Free Space" value, the rsync job on the QNAP stopped when the following happened, the Unraid had NO disks with a full 5.2TB available and reported a error message reporting that not enough space was available.  I would have expected that that file would not be transferred, but that the smaller files would be transferred.  Assume that is an issue with QNAP HBS3 rsync handling but not sure.  In any case, since Unraid is unable to split large files, I probably need to rethink this and perhaps find a way to have my image files split up into ie VMDK's into 500gb chunks if I wish to utilize Unraid.  Thank you for the feedback.

You have a problem which most current Unraid users don't have to think about.  (You would have less of a problem IF you had an 80TB array which was made up of five 16TB drives.)

 

You might want to think about how/why you end up with a 5.2TB image file, what is in that file, how long it needs to be preserved, and how much of it is fluff rather than data that needs to be archived.

 

 

As Frank1940 suggested, the best solution to this issue is to ensure any drives on my QNAP NAS that I am backing up to Unraid should be a smaller size.   I tuned parameters in my disk imaging software to split at 500gb so that I would not run into this issue in the future.  I chose not to increase the size of my unraid disks since I use Unraid for my repurposed hardware and one of the attractions of Unraid is the ability to mix and match disk sizes.

 

The issue that I found  is during an SMB tranfer, if Unraid does not have space for a file of that size, the entire transfer will fail at that point.