On 22.02.2012 03:15, Steve Tatlow wrote:
Hi,
We are running squid as a transparent proxy, with dansguardian doing
the
content filtering. All traffic will be coming from localhost and no
authentication is required. Can someone tell me how I ensure there
are
enough squid processes to support a large number of users (maybe 250
concurrent users)
None of us can tell you specific numbers. It is dependent on your
hardware and client traffic.
The thing to be aware of is that measuring in users is meaningless. One
user can flood the proxy, or some thousands could leave it idle waiting
for more work. Capacities are reliably measured only in requests per
second.
To get the details you seek measure and get some idea of how many
requests per second those users make at peak times, and how many the
whole structure is capable of handling.
Each Squid series has a theoretical limit which is hardware dependant
(3.1 can do about 800 req/sec on a dual core 2.2GHz CPU etc). The
configuration specifics you create and type of requests the clients will
reduce the capacity limit from there.
With content filtering you can usually expect only to reach 30% of
Squids regular throughput due to the content processing overheads.
250 users is not large for Squid. Any of the production releases should
be able to handle that many without causing much of a CPU bump on modern
hardware. I think you can start with one Squid process and expand to
more if you find it stressing the machines. More likely you will need
more DansGuardian proxy processes though, that is where the heavy CPU
consumption will occur.
Amos
