Squid_ The Definitive Guide - Duane Wessels [136]
dns: Dnsserver Statistics
This cache manager page is available only when you use the —disable-internal-dns option. In this case, Squid uses a number of external dnsserver processes to perform DNS lookups. The dnsserver program is one of a number of helper processes Squid can use. The other types of helpers are redirectors, authenticators, and external ACLs. All Squid's helpers have cache manager pages that display the same statistics. For example:
Dnsserver Statistics:
number running: 5 of 5
requests sent: 3001
replies received: 3001
queue length: 0
avg service time: 23.10 msec
# FD PID # Requests Flags Time Offset Request
1 6 20110 128 AB 0.293 0 www.nlanr.net
2 7 20111 45 A 0.000 0 (none)
3 8 20112 4 A 0.000 0 (none)
4 9 20113 0 A 0.000 0 (none)
5 10 20114 0 A 0.000 0 (none)
The number running line shows how many helper processes are running and how many should be running. The dns_children directive specifies how many dnsserver processes to use. The two numbers should match, but they may not if a helper process dies unexpectedly or if some processes could not be started. Recall that when you reconfigure a running Squid instance, all the helpers are killed and restarted. See the discussion in Appendix A.
The requests sent and replies received values display the number of requests sent to (and responses received from) the helpers since Squid started. The difference between these two, if any, should correspond to the number of outstanding requests.
The queue length line shows how many requests are queued, waiting for one of the helpers to become free. The queue length should usually be zero. If not, you should add more helpers to reduce delays for your users.
The avg service time line shows the running average service time for all helpers. Your particular value may depend on numerous factors, such as your network bandwidth and processing power.
The next section displays a table of statistics for the running dnsserver processes. The FD column shows the file descriptor for the socket between Squid and each dnsserver process. Similarly, the PID column shows each helper's process ID number.
The # Requests column shows how many requests have been sent to each helper. These numbers are zeroed each time you reconfigure Squid, so they many not add up to the total number of requests sent, as shown earlier. Note that Squid always chooses the first idle helper in the list, so the first process should receive the largest number of requests. The last few processes may not receive any requests at all.
The Flags column shows a few flags describing the state of the helper process. You should normally see A (for Alive) in each column. Occasionally, when the helper process is handling a request, you'll see B (for Busy).
The Time column displays the amount of time elapsed (in seconds) for the current, or last, request. Offset shows how many bytes of the response message Squid has read on the socket. This is almost always zero. Finally, the Request column shows the request that was sent to the helper process. In this case, it is either a hostname or an IP address.
redirector: URL Redirector Stats
The Redirector Stats page is available only if you are using a redirector (see Chapter 11). The format of this page is identical to Dnsserver Statistics, described earlier.
basicauthenticator: Basic User Authenticator Stats
This page is available only w ith the ./configure —enable-auth=basic option and when you define a Basic authenticator with the auth_param basic program directive. The format of this page is identical to Dnsserver Statistics, described earlier.
digestauthenticator: Digest User Authenticator Stats
This page is