The maximum amount of time a client (browser) is allowed to
remain connected to the cache process. This protects the Cache
from having a lot of sockets (and hence file descriptors) tied up
in a CLOSE_WAIT state from remote clients that go away without
properly shutting down (either because of a network failure or
because of a poor client implementation). The default is one
day, 1440 minutes.
NOTE: The default value is intended to be much larger than any
client would ever need to be connected to your cache. You
should probably change client_lifetime only as a last resort.
If you seem to have many client connections tying up
filedescriptors, we recommend first tuning the read_timeout,
request_timeout, persistent_request_timeout and quick_abort values.