I’m transferring data from a mounted unassigned disk to my array, and I want to confirm that I’m doing it correctly.

I originally tried using Krusader, but I couldn’t get the WebGUI to load (I’m on unRAID 7.1.4, and most tutorials seem to be for older versions), so I switched to the built-in file management method.

Here’s what I did:

1. On the Main tab, I clicked the unassigned disk, drilled down to the folders, and selected the files I want to copy using the check-boxes.

2. I clicked the Copy button at the bottom, selected the destination folder: /mnt/user/media/Movies/

3. Then I clicked Start to begin the copy.

Questions:

• Is this the correct way to do it? I’ve read warnings about potential data corruption when moving files directly between a disk and the array vs. going through a user share, so I want to make sure this method is safe and my data will remain intact.

• Is using this built-in copy method essentially the same as using Midnight Commander (MC) in older versions, or is there an advantage to using MC instead?

• The copy speed seems slow, around 42–50 MB/s after the first minute. It starts at ~170 MB/s but drops quickly. Is this normal for this method, or is there a better way to transfer large amounts of data?

System Context

• Single array: 2×8TB HDDs

• Parity: 1×8TB HDD

• Cache pool: 1×500GB SSD

The warnings are about moving/copying between array (or pool ) and user shares. This is because Linux doesn't know that user shares are just another view of the disks and pools, and so it might try to overwrite what it is trying to read.

MC or Krusader could let you make this mistake. The built-in file manager won't let you make this mistake.

Also, Unassigned Devices are not part of the array, pools, or user shares, so not affected by this at all.

The initial burst of speed is due to ram buffering. The slower speed you experienced is typical of array writes, since parity is updated at the same time. Turbo mode might help. See here for more about how array writes are done:

https://docs.unraid.net/unraid-os/manual/storage-management/#array-write-modes

Fastest method for initial data load is to leave parity unassigned until transfer is done, then build parity after.

Also, if you need to transfer more at one time than cache can hold, don't cache.

Thanks for all of the insight and suggestion about reconstruct write - files are now copying to the array at ~100 MB/s!