Server BMCs can need to be rebooted every so often

Re:Server BMCs can need to be rebooted every so often by isopede on Sunday January 15, 2023 @03:53AM (#34387916)

A few of my recent systems have come with a built-in combo BMC on the motherboard NICs. I haven't seen this before, is it a new trend? I'm imagining they put in a switch in there with the NICs? How does this even work?

I'm doing a few timing sensitive projects involving hardware timestamping in the NICs. Does this mess with say timing variability? I've disabled the BMCs out of paranoia but I don't know the topology inside.

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Re:Server BMCs can need to be rebooted every so often by shenki0 on Sunday January 15, 2023 @03:56AM (#34387934)

NC-SI. It allows the BMC and the host to share a single physical network connection.

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Re:Server BMCs can need to be rebooted every so often by gnufx on Sunday January 15, 2023 @08:18AM (#34389181)

That's common, and something to avoid. You want a physically separate BMC network for security and reliability.

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Re:Server BMCs can need to be rebooted every so often by ilyt on Sunday January 15, 2023 @09:31AM (#34389651)

One example: on some servers turning off NIC will... turn off the port completely, including shared BMC connection hanging off it.

Which happens during reboot meaning you won't catch the boot screen on KVM if you use shared nic

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Re:Server BMCs can need to be rebooted every so often by gnufx on Sunday January 15, 2023 @01:18PM (#34391592)

What I remember was losing it just at a crucial point in the PXE boot process. You're also dependent on the same switches as the main net, and have to rely on fragile firewalling or VLANs to restrict access to the BMCs.

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