the cache files are copied from the nfs server to the local node, and they get the timestamp of the local server.

assume this case:

• one installation using DFS, with webnodes A and B
• at time X, all caches are cleared on both servers
• a request someURL arrives to node A
• at time X+15min, the same request someURL goes to node B

at time X, caches are generated for nfs and node A. both servers get the copy of the cache file with a timestamp X
at X+15min, the server B makes the request, and the cache file is copied from nfs to the local var/ dir. the copy on server B will get a timestamp of X+15

now, assume that caches have a span of 1.00 hour. 1.05h later, 2 requests for the same someURL arrive at the same time, one lands on server A, another on server B.

the server A sees the cache as expired, will trigger a new cache generation. expected result.

the server B sees the cache still alive, and serves the old cache, until it reaches the 1.00 hour limit, which happens only at X+15min. so, there is a window of 15 minutes where the server B is serving the wrong cache

in more generic terms, in a multi node DFS cluster, the servers will retain the invalid caches for the interval between the cache generation and each server individual request.