LS-WXL very slow backup and cant access files

[PhilipJW]

My Linkstation LS-WXL is set to back up to an extrenal USB hardrive every month.

It started the process on 1st August as normal but seems to be running incredibly slowly.

In addition while it is running no system can access the files (although I can see them in explorer). For example I use the NAS drive primarily as a media server and none of my media players can access the files ie my smart TV cant see the video files to play them and the music system (Sonos) cannot index the music files or play them.

I can even access the NAS using the web interface to see what is happening so my questions are:

Is there any way to see what the transfer rate between the NAS and the backup drive?
Why is it running so slow and preventing access from other systems including the web interface?
If I reboot the NAS during the backup does that cause any problems?

Thanks