On the OS Administration page, I see 3 lines that look like this.
Total Free Used
Disk/active 12317944K 900628K 10791588K (93%)
Disk/inactive 12317912K 9827636K 1864548K (16%)
Disk/logging 43090196K 15817756K 25083588K (62%)
Is this normal to see the active disk at 93% used?
Yes, this is normal behaviour with CM 5.x. I've seen over 20-30 5.1 servers where the disk utilization is wither 92 or 93%. I've confirmed the same with new installs without having added/changed any setting on the box.
With the active partition around with 93% utilization is normal.