NFS Services Administrator's Guide

Troubleshooting NFS Services
Performance Tuning
Chapter 8 331
The number of collisions (Coll) divided by the number of output
packets (Opkts) is the collision rate. If your collision rate is greater
than 10%, consider dividing your network into smaller segments and
putting an NFS server on each segment. See Installing and
Administering LAN/9000 Software for information on dividing your
network.