RE: [fw-wiz] PIX-515 acceptable CPU usage?
From: Eugene Kuznetsov (eugene_at_datapower.com)
To: "'Ahmed, Balal'" <firstname.lastname@example.org>, "'Adam Greene'" <email@example.com>, <firstname.lastname@example.org> Date: Thu, 16 Sep 2004 13:51:19 -0400
> Some time ago cisco Documentation used to say that if your
> PIX firewall is running at 30% sustained utilization then
> an upgrade is advised. The latest
It is worth noting that for many network device products, it is difficult
for the vendor to provide a really accurate CPU utilization metric. There
may be custom hardware assist, multiple processors, NPUs, and so on. It is
not easy to reduce all of that to a single percentage.
Also, such numbers are rarely linear. In other words, if a device is at 30%
utilization right now, 2x more traffic won't drive it to 60% -- it may be
40% or 100%, depending on the internal architecture.
Some less ethical vendors will actually fudge their utilization metrics as a
competitive tactic, i.e. "look, we're only at 5% utilization while
saturating the network".
So it's a useful basic health check, but be careful in placing too much
trust in CPU utilization numbers, in PIX or elsewhere.
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