💾 Archived View for 9til.de › lobsters › n6vtps.gmi captured on 2023-11-14 at 07:48:04. Gemini links have been rewritten to link to archived content
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Viewing comments for "Debian on Mellanox SN2700 (32x100G)"
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adamcstephens commented [3]:
That's really amazing. I wish such switch support was much
more common and included options that have 1G copper ports.
dist1ll commented [1]:
That's a really great article.
But can someone help me understand why a switch needs a 64-
bit multicore processor, 8 gigs of RAM and run Linux (though
this is not unique to SN2700, just a general observation)?
I was under the impression that switches (both L2 and L3) do
all performance-sensitive work in hardware.
> hobbified commented [10]:
There are some exceptional cases that need to be offloaded
to a real CPU, plus you want to be able to support at least
a bit of monitoring and statistics. When you've got 32 ports
and an aggregate switching capacity of 5 billion packets
per second, you don't want that CPU to be too poky, and on
a $25,000 device you can probably afford to spend $100 on
the CPU instead of $10 if it opens up some flexibility for
your customers. And reading the part of the article about
switchdev (and knowing a bit about Mellanox's history with
Linux), flexibility was definitely their intent.
> fanf commented [3]:
Switches do a bunch of control plane stuff, things like STP,
LLDP, VXLAN, etc. usw. Dunno how much if that is in the data
plane on this device :-)
Switches also need some kind of CLI for configuration, and
it makes sense to use Linux for that. It can also act as
the front-end processor for the data plane, e.g. feeding it
firmware at boot time.
> proctrap commented [2]:
The last 50G firewall I ordered is also a bunch of mellanox
cards and an EPYC processor - if you hit the CPU with your
traffic for whatever reason (things you can't offload to
the network cards), then you better have enough compute
for that..
You can do way more than VLANs on such a thing, like NAT,
VPN, VRF and other routing stuff. For firewalling you might
also hit the CPU, depending on what you want to filter (and
what your hardware offloading can do).
symgryph commented [1]:
I was thinking about buying these until I read how many
decibels 70!
> drawks commented [1]:
I think that is if the fans are all running full bore. The
author mentions early in the article that the fan speeds
are controlled by software and required a calibration with
pwmconfig before they dropped down to not running at 100%
duty cycle
> bitbckt commented [1]:
They're really not that loud. I run one in my house at 30%
fan speed, and it's quieter than almost any other actively-
cooled switch I've used - certainly quieter than any DC
grade switch I've been around. Very low power for the
throughput, too.
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