Sep 8 21:25:01 NEOMAETSSOLERA01 disk_subsystem[19374]: snlog: sn="bc:30:5b:f5:38:43" id="DS" m="23" c="6" event="DISK_STATUS" category="HARDWARE" ip="172.20.12.36" model="R720xd" msg="Adapter 1; seqNum: 0x00055756; Time: Thu Sep 8 22:22:49 2016; Event Description: PD 1d(e0x26/s3) Path 5000c50055990f46 reset (Type 03); Device ID: 29; Enclosure Index: 38; Slot Number: 3; "
The tail end of the line indicates, in this case, slot 3. If the slot number changes regularly, then this is a good candidate for a firmware update rather than a drive replacement.
The steps to update the Seagate drive firmware are: