I just upgraded my parity drive by powering down the system and putting the new drive in the same slot as the old parity drive.  Upon re-starting, the screen says its upgrading parity, but does not give me any indication that something is happening.  Do I need to start the sync?  Manual says it will automatically rebuild parity, but I expected to get a % complete similar to when you check parity.  Here's my screenshot:

 

Yep, just click the 'I'm sure I want to do this' checkbox and then click 'start'.  The data-rebuild will begin.  Once that is done, run a parity check.  Once the parity check completes, you are done.  You can then add the old parity drive as a new data drive if you wish (although many people prefer to leave it intact for a few weeks just in case your new one dies).

 

By the way, you also may want to upgrade your version of unRAID to 4.5.6 or 4.6-rc5.

The manual is wrong.  It will not automatically start calculating parity. 

It will wait for you to check the checkbox under "Start" and then click it to begin the process.

 

You are not the first to think it has started... one user waited for days before asking if it should take so long.

 

Joe L.

Thanks everyone.  Worked great.