Sun Microsystems Sun GlassFish Enterprise Server 2.1 Tuning Manual page 62

HTTP Service Settings
HitRatio
The hit ratio is the number of cache hits divided by the number of cache lookups.
This setting is not tunable.
Note –
addresses will appear instead of host names in log files.
Caching DNS Entries
It is possible to also specify whether to cache the DNS entries. If you enable the DNS cache, the
server can store hostname information after receiving it. If the server needs information about
the client in the future, the information is cached and available without further querying.
specify the size of the DNS cache and an expiration time for DNS cache entries. The DNS cache
can contain 32 to 32768 entries; the default value is 1024. Values for the time it takes for a cache
entry to expire can range from 1 second to 1 year specified in seconds; the default value is 1200
seconds (20 minutes).
Limit DNS Lookups to Asynchronous
Do not use DNS lookups in server processes because they are resource-intensive. If you must
include DNS lookups, make them asynchronous.
Enabled
If asynchronous DNS is disabled, the rest of this section will not be displayed.
NameLookups
The number of name lookups (DNS name to IP address) that have been done since the server
was started. This setting is not tunable.
AddrLookups
The number of address loops (IP address to DNS name) that have been done since the server
was started. This setting is not tunable.
LookupsInProgress
The current number of lookups in progress.
62 Sun GlassFish Enterprise Server 2.1 Performance Tuning Guide • January 2009
If you turn off DNS lookups on your server, host name restrictions will not work and IP