BTRFS - Script for mirror-rebuild status

I just tried out rebuilding a BTRFS-Mirror with a new SSD. I found out there is no integrated way to monitor the mirror-rebuild status.

So I created a little script which monitors the status of the rebuild every 5 Minutes and notifies to the notification center.

The script might be far from perfect, but I thought I would share for anyone desperate for more infos.

Any upgrades are welcome!

Just create a new script in User-Scripts and enter the name of your cache in the first variable. Mine is "qvoraidone".

As soon as you replaced the broken SSD with a new one and started the array, you can let the script run in the background.

#!/bin/bash
#Enter name of cache to rebuild!
cache="qvoraidone"
#Variable for notification-timer in seconds
notificationtime="300"
#Putting the btrfs command into a variable
distribution="btrfs device usage /mnt/$cache/"

#Start a loop to notify the user every $notificationtime seconds about the status
while true
do

    #Make it multiline
    multilinedistribution="$($distribution \
    )"

    #Get the two lines with "Data,RAID1 " and Capture anything until the first "G".
    #Then put "o1"(only Group1), so everything between "Data,RAID1 " and "G" into a variable.
    #Looks like this "105.00 30.00"
    datasize=$(pcregrep -o1 '.*Data,RAID1: ([^G]+)' <<< "${multilinedistribution}")
    
    #Exchange the "." with "," - Not needed anymore
    #datasizecomma="${datasize2//./$','}"
    #echo datasizecomma $datasizecomma
    
    #Put them in an array for calculation
    array=($datasizecomma)
    array=($datasize)

    #Determine which is the larger number
    if [ ${array[0]} \> ${array[1]} ]
    then
        #calculate the percentage of the larger number
        echo ---------------------------
        status=$(awk "BEGIN {print ${array[0]}/${array[1]}*100}")
        echo "BTRFS-Rebuild status: "$status"% completed!"
        /usr/local/emhttp/webGui/scripts/notify -i normal -s "BTRFS-Rebuld still in progress!" -d ${array[0]}"GiB/"$status"% mirrored!"
        sleep $notificationtime
    else
        if [ ${array[1]} \> ${array[0]} ]
        then
            #calculate the percentage of the larger number
            echo ---------------------------
            status=$(awk "BEGIN {print ${array[1]}/${array[0]}*100}")
            echo "BTRFS-Rebuild status: "$status"% completed!"
            /usr/local/emhttp/webGui/scripts/notify -i normal -s "BTRFS-Rebuld still in progress" -d ${array[1]}"GiB/"$status"% mirrored!"
            sleep $notificationtime
        else
            #Determine if the numbers are equal
            if [ ${array[1]} \= ${array[0]} ]
            then 
                echo ---------------------------
                echo "Rebuild finished! "${array[0]}"GiB mirrored!"
                #Info to unRAID
                /usr/local/emhttp/webGui/scripts/notify -i normal -s "BTRFS-Rebuld finished!" -d ${array[0]}"GiB mirrored!"
                break
            else
                echo "ERROR, calculation failed!"
                #Warning to unRAID
                /usr/local/emhttp/webGui/scripts/notify -i alert -s "BTRFS-Rebuild Error!" -d "Could not calculate progress! Is "$cache" mounted?!"
                break
            fi
        fi
    fi
done

#More output
echo ---------------------------
echo "Data, single needs to be 0!"
echo "Data,RAID1 needs to be identical to be finished!"
echo ---------------------------
echo "Distribution"
echo ---------------------------
$distribution