[CentOS] Performing post-installation setup tasks - for 75 minutes

I'm doing a new install, and everything seems to have gone fine apart from the incredible amount of time it's taken.

It does have 6 x 4TB drives in RAID6 and I am installing from a USB DVD drive as I had no SATA ports left, but this is getting rediculous.

I chose a simple install (the one above file and print server) and added Postgresql but that was about it.

It took over 5 hours to do the install and at 16:50 it changed to

Performing post-installation setup tasks. That was 85 minutes ago. The HDD light keeps flashing, but other than that (and the circle swirling) there doesn't seem to be any activity.

Is this normal and can I check to see if it is actually doing something?