No, you should not wait; either your drive has failed completely or it's on the verge of doing so. See
this faq for more information about what the impact of a failed drive is.
My recommendation is to halt the removal (if you can), shut your server down, and disconnect the drive. It will then show as "missing". At that point, you can remove the drive. If there's enough free space (it sounds like there should be), Windows Home Server
should re-duplicate everything; if there's not enough space to re-duplicate everything, you will see errors reported in the console, which means you will need to add a drive to server storage for your server to re-duplicate all your files.
Once you've finished adding the drive, and your server has re-duplicated everything, use the backup database Repair button in the console.
In the future, I would recommend against the use of external drives in server storage (they're fine as backup drives).
I'm not on the WHS team, I just post a lot. :)
