The 60-drive DAC doesn't have the disks on the front side like the 15-drive DAC, so the process to physically replace faulty disks is slightly different.
The 60-drive DAC 4U enclosure is a drawer-type of DAC that slides in and out of the rack with access to the drives from the top. The disk drives, LCCs, and cooling modules are located inside the DAC.
First of all, follow the steps in the Disk Replacement guide in the following link to prepare the appliance, then in the step "Physically replace the drive", follow the rest of the steps in this article: https://community.rsa.com/docs/DOC-57956
This is the front view of a 60-drive DAC:
To gain access to the disks, follow these steps:
Unlock and remove the front bezel. Next, to unlock the DAC from the rails, pull on the orange loops on each side of the DAC. Finally, pull the orange tabs on each side of the DAC to slide the DAC out of the rack on its rails until it locks into the secure service position.
The following picture shows an example of a 4U DAC with the top cover closed:
Slide the top cover out to get access to the interior of the DAC:
The following picture shows an example of the interior view of a 4U DAC:
Locate and replace the disk:
The disk drives for the 4U DAE are encased in cartridge-style enclosures. This enclosure is used so that varied types and sizes of disk drives can be supported. Each cartridge has an easy-to-pull and push latch. The latch allows you to quickly and efficiently snap-out a disk drive for removal and snap-in for installation.
The left side (red in the picture) corresponds to the first enclosure that you will see in the nwraidutil output, the right side (green in the picture) corresponds to the second enclosure that you will see in the nwraidutil output. Therefore, these internal enclosures will show with a different enclosure number in the nwraidutil, each of them with 30 disks and the disk numbers will alternate on every 6 disks (see below example of nwraidutil for better understanding): Image description