Gaetano Giunta wrote:
Q1: Reading the archives of this mailing list, I concluded that squid
does not support using keep-alive in connections to source servers.
I assume that setting keep-alive On on an Apache source server cached by
squid would thus be harmless: since squid does not do keepalives, the
connections would be terminated immediately - Apache would waste time
keeping processes busy waiting on sockets after squid terminated its
http/1.0 request.
The advantage being that is the same apache server serves some other
site beside the one cached by squid, or if squid is disabled
temporarily, keepalives will be automatically in effect.
Is this correct? Are there any advantages/drawbacks that are escaping me?
The conclusion that Squid does not support keepalive is incorrect. Note
the default config setting.
http://www.squid-cache.org/Doc/config/server_persistent_connections/
Also, HTTP/1.0 protocol assumes that keepalive is off unless explicitly
stated as provided. Thus Apache receiving HTTP/1.0 request without
keepalive permitted will result in the Apache will terminate the
connection or send back a reply explicitly requesting the proxy to do
keepalive.
When Squid closes any connection the far-end always receives a FIN or
RST TCP message. They are not left hanging waiting for data.
Q2: Using squid as reverse proxy, I have seen that a lot of sockets (200
to 300) are always listed on the origin server, coming from the squid
server, in TIME_WAIT status.
Using netstat on the squid server itself at the same time, I see about
10 open sockets, none of which in TIME_WAIT.
Is this normal? Is it a sign of some misconfiguration? (note: there is
probably a firewall currently sitting between the two servers). Can it
be related somehow to keepalives?
Maybe yes, maybe no. More likely related to unknown-length objects with
the server closing the connection after each send to signal end-of-object.
TIME_WAIT only means that the sockets were previously used (even if
closed properly) and are waiting the TCP timeout before safe re-use.
Amos
--
Please be using
Current Stable Squid 2.7.STABLE9 or 3.1.1
