March 17, 20251 yr I am transferring files between NAS and Unraid and it seems like after each batch completes, Unraid seems to keep writing to the array indefinitely as if the files were still being transferred although it is already done. I see this in the Main tab (read and write). There is disk activity seen in the HDD light in the case for the specific disk that was being used plus the 2 parity disks, though I don't see anything new being written to the disk. There is no cache and no mover for the array. Anyone else seeing this too or am I crazy? I wait for a while to see if it will stop but it does not seem to stop on its own, so I just stop the array and start again, no more activity. Using xfs for FS.
March 18, 20251 yr Community Expert Solution Unraid does use free RAM to buffer writes to disks to speed up data transfers. If you have abundant RAM available on your system, it can take a long time to actually finish transferring all the data to the hard disks after your PC's file manager has transfer the last byte to your Unraid server. (Write speeds to a parity protected array are generally no faster than about 50% of the transfer rate of the slowest hard disk in the current operation. If you are writing lots of small files, (I have seen) the hard disk write speed drop into the 5-10MB/s range due the file processing overhead!)
March 18, 20251 yr Author 31 minutes ago, Frank1940 said: Unraid does use free RAM to buffer writes to disks to speed up data transfers. If you have abundant RAM available on your system, it can take a long time to actually finish transferring all the data to the hard disks after your PC's file manager has transfer the last byte to your Unraid server. (Write speeds to a parity protected array are generally no faster than about 50% of the transfer rate of the slowest hard disk in the current operation. If you are writing lots of small files, (I have seen) the hard disk write speed drop into the 5-10MB/s range due the file processing overhead!) I have 192GB of RAM and I am moving TBs of data across to Unraid. I tested with some different transfers and it takes several minutes after the file transfer ends before the array goes quiet, but it does seem to end eventually so this makes perfect sense.
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