This shows the number of entries in the DNLC (Directory Name Lookup Cache). The DNLC caches pathname to inode lookups.
An understanding of operating system internals may be required to properly interpret this statistic.
This may be useful to check if a workload accesses millions of small files, for which the DNLC can help.
If there are generic caching issues on the appliance, first check the Cache: ARC accesses statistic to see how well the ARC is performing, and the Protocol statistics to understand the requested workload. Then, check the Advanced Analytic Cache: ARC size for the size of the ARC.