The NIS client looks up the NIS user and netgroup maps every 30 minutes and caches them. A refresh clears the cache and performs the lookup again.
If you are using NIS to check user group permissions in order to authorize file access, the cached user entries are used. To avoid unwanted access denials, it's good practice to refresh the cache immediately after you update any user's group memberships on NIS.
The user cache is limited to 20,480 users.
If you are using NIS netgroups to determine which hosts are allowed to access NFS exports, refreshing the cache can help avoid delays when granting access. If a host requests to access an export and is not found in the netgroups that are listed in the view policy, VAST Cluster fetches the netgroup map again. Therefore, a host that was recently added to a netgroup without a cache refresh would be granted access after a short delay. To avoid those delays, refresh the NIS cache immediately after updating the netgroup map.
The netgroup cache is limited to 10,000 entries. If the number of netgroups on the NIS server exceeds the limit, the least recently used netgroups are skipped each time the netgroups are fetched.
To refresh the NIS cache:
From the left navigation menu, select User Management and then NIS.
Open the Actions menu for the NIS configuration record and select Refresh.
A loading icon appears while the cache is refreshing. When finished, the page returns to normal and a message is displayed.