I can't seem to find the answer to this. I am about to replace the smallest drive in my RAID with a larger one. I know when I pull the small one that it will automatically rebuild. I want to put the new drive in and validate it while it's rebuilding. The last time I had this issue I did the rebuild first, then once it was done, I added the new drive and validated it. Is it dangerous to do both tasks at the same time? I am planning on leaving the computer entirely for a few days until it's done so I don't screw anything up but I wanted to ask if this is safe.
You cannot do both at the same time. Best is validate the volume first. This updates all parity info. then replace a disk. The rebuild is like a valdiate, so no need to do it a second time.

