[OmniOS-discuss] LACP Omnios , igb and C3750

[Jim Klimov]

13 декабря 2014 г. 23:07:40 CET, Doug Hughes <doug at will.to> пишет:
>
>On 12/13/2014 4:53 PM, Paul B. Henson wrote:
>> On Sat, Dec 13, 2014 at 11:12:35AM -0500, Dan McDonald wrote:
>>> I thought I'd mentioned this on the thread, but does the machine
>>> attempt to use one of the IGB interfaces for IPMI as well?  We do
>not
>>> support dual-use NICs like that.  (Check your BIOS.)
>> Hmm, I had thought that the "shared" IPMI port was invisible to the
>OS?
>> That there was an internal three-port switch, with one port connected
>to
>> the physical jack on the back of the server, and then the other two
>> wired internally to the NIC on the motherboard and the NIC on the
>BMC?
>>
>> Do these boxes do something else that actually tweaks with the
>hardware
>> on the motherboard NIC when the BIOS is set to shared?
>>
>That's the typical setup with IPMI NIC = shared. The OS is totally 
>unaware that there's another device using the same hardware. The
>amazing 
>thing is that while the OS is using the physical port at 1gbit the BMC 
>is using it at 100mbits/sec on the same physical port, all without 
>either knowing about the other. IMHO, the best way to do this is to set
>
>the IPMI to use a different VLAN than the host, but that's dependent on
>
>the features of your BMC and network hardware. (tagged to BMC, untagged
>
>to host).
>
>The other options are 'dedicated' where there's a dedicated IPMI/BMC 
>port, and 'failover' which has a dedicated port, but can failover to
>the 
>motherboard/host port. (crazy: some of them even support bonding across
>
>the ports for the BMC; who thought this was a good idea?!)
>
>
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Imho it varies with hardware and firmware. Recent supermicros apparently offer, among other configurable options, failover between a dedicated ipmi port (deemed more reliable) and the connection shared over a port of the server (saves on cabling) if both ports have a cable. According to forum critique, this implementation is currently prone to failure if the datacenter takes time to power on and for the switches (STP) to converge and begin passing frames. The ipmi module sticks to one choice it made during bootup and no longer fails over if that link goes down. Something of the sort, they say.

What i did have experience with was with sun x2100, where they had 2*bge + 2*nge (less reliable in practice under load) interfaces, and one of the better ones was shared with ipmi, and a reboot of the host using the interface caused the ipmi module to lose connection. So essentially that port was to be left unconfigured in the OS, for remote management to remain usable when you need it.

Jim
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