Not sure if anything like this exists already - never found anything in my brief searches a few years ago. Decided to post what I built - using info I scoured on these forums and elsewhere. Just wanted to share what I had - in case this helps anyone else.

The script uses information Unraid provides as updates in /var/local/emhttp/var.ini. The script is by now means complete and clean - but it gives me a fairly good idea of time to parity check/rebuild completion and/or current status. There's no clear error-checking either - consider this beta code at best. It does not write any data to any partitions - the worst it will do is provide inaccurate data.

Script execution

The script can be run on its own to show current status of data/parity check/rebuild.

root@daffy2:~# rstat

   Type:  check P Q

Current:  17125324848 ( 17.54 TB )

   Size:  19531825100 ( 20.00 TB )

Percent:  87.68%

If you pass a numeric value it will estimate the current speed and show a completion time - based on that speed.

root@daffy2:~# rstat 20

   Type:  check P Q

Current:  17041739152 ( 17.45 TB )

   Size:  19531825100 ( 20.00 TB )

Percent:  87.25%

  Speed:  136.58 MB/s ( 20 seconds average )

Remain:   5.06 Hours

Edit - The attached .txz places the script, named rstat, in /usr/loca/bin. I placed this file in /boot/extra/ so it is loaded into Unraid filesystem upon each boot. Not sure if this is the best approach. I'm open to ideas - but this seems to work great for me.

rstat-0.8.5-custom.txz

Edited August 2Aug 2 by nocternal
Additional info

If you have the parity check tuning plugin installed then you get the new command 'parity.check' installed that allow you to query the parity check status amongst other things. It does not provide exactly the same information as your script (although it would be easy to enhance it to do so if there is a demand).

Do you want me to enhance the "parity.check status" command in the parity check tuning plugin to provide the additional detail so you do not need to maintain your script?

Sorry for the delay in replying.

@itimpi - I'll need to checkout the parity check tuning plugin! Would be nice to get as much details as possible on CLI. I don't run a parity check too often (and my disks have been stable for several years - so no data rebuilds required). My parity drives are fairly large - so nice to keep an eye on parity check when I do. Let me know if you need any help/testing any changes. I have a second backup unraid box (with all my older drives in it) I can run tests on.