Specifies the maximum number of redirector processes that Squid may
spawn (numberofchildren) and several related options. Using too few of
these helper processes (a.k.a. "helpers") creates request queues.
Using too many helpers wastes your system resources.
Usage: numberofchildren [option]...
The startup= and idle= options allow some measure of skew in your
tuning.
startup=
Sets a minimum of how many processes are to be spawned when Squid
starts or reconfigures. When set to zero the first request will
cause spawning of the first child process to handle it.
Starting too few will cause an initial slowdown in traffic as Squid
attempts to simultaneously spawn enough processes to cope.
idle=
Sets a minimum of how many processes Squid is to try and keep available
at all times. When traffic begins to rise above what the existing
processes can handle this many more will be spawned up to the maximum
configured. A minimum setting of 1 is required.
concurrency=
The number of requests each redirector helper can handle in
parallel. Defaults to 0 which indicates the redirector
is a old-style single threaded redirector.
When this directive is set to a value >= 1 then the protocol
used to communicate with the helper is modified to include
an ID in front of the request/response. The ID from the request
must be echoed back with the response to that request.
queue-size=N
Sets the maximum number of queued requests. A request is queued when
no existing child can accept it due to concurrency limit and no new
child can be started due to numberofchildren limit. The default
maximum is zero if url_rewrite_bypass is enabled and
2*numberofchildren otherwise. If the queued requests exceed queue size
and redirector_bypass configuration option is set, then redirector is
bypassed. Otherwise, Squid is allowed to temporarily exceed the
configured maximum, marking the affected helper as "overloaded". If
the helper overload lasts more than 3 minutes, the action prescribed
by the on-persistent-overload option applies.
on-persistent-overload=action
Specifies Squid reaction to a new helper request arriving when the helper
has been overloaded for more that 3 minutes already. The number of queued
requests determines whether the helper is overloaded (see the queue-size
option).
Two actions are supported:
die Squid worker quits. This is the default behavior.
ERR Squid treats the helper request as if it was
immediately submitted, and the helper immediately
replied with an ERR response. This action has no effect
on the already queued and in-progress helper requests.