[Linux-PowerEdge] BMC and NIC #1 interaction

Spike_White at Dell.com Spike_White at Dell.com
Wed Aug 5 11:46:59 CDT 2015

That's because you're using "shared NIC" mode.

Long ago, internally we deployed some early servers in "shared NIC" mode.   We've got a few dusty lab servers yet that may still use that.

But overall, we've eradicated this from our env.  You mainly need a DRAC when a server drops off the network.  As you see, often in "shared NIC" mode - that's precisely when it's unavailable!

Low-end TOR switches are so cheap now, we use a dedicated DRAC TOR switch in each cabinet.  And run in "dedicated NIC" mode.

I envision another problem with "shared NIC" mode as well.  You can attach to only one switch.  For any important server, we bond our public interfaces active/backup and use dual TOR public switches.   We bond using Linux' bonding modules.  So that if we lose any single public TOR switch - no server downtime/business impact.

Yes, we still have one single DRAC TOR switch.  But if that single DRAC TOR switch dies, we can SSH into the boxes and diagnose.  Also can replace the DRAC switch w/ no server downtime/business impact.


Message: 4
Date: Wed, 5 Aug 2015 08:39:22 -0500
From: Chris Adams
Subject: Re: [Linux-PowerEdge] BMC and NIC #1 interaction
To: linux-poweredge at dell.com
Content-Type: text/plain; charset=us-ascii

Once upon a time, Ruben Laban said:
> Unfortunately, at this point em1 was the only interface with an IP
> configured and thus lost my SSH connection. Luckily I had finally
> managed to get SOL console redirection operational. However, when I
> tried to open SOL connection all I got was timeouts. It seemed that
> the BMC had dropped off the network as well. Once I got a colleague to
> bring up em1 again, the BMC also started working again.
> Is this expected behavior??

It seems to be, yes. If the OS sets the link PHY down, the BMC is not smart enough to override it. I've had other systems with a shared NIC for OS and IPMI, and they handled that, but all the Dells I've tried with a shared NIC work this way.

Chris Adams
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