'no buffer space available' after switch goes down on freeBSD 7.3

[Adrian Chadd]

On 21 December 2012 04:13, Tsaregorodtsev Denis <telemat at extrim.it> wrote:
> Hello,
>
> I maintenance ISP's DNS server which works under FreeBSD 7.3 and BIND
> 9.9.1-P4. The network adapter is Intel(R) PRO/1000 Network Connection,
> driver - em. The server is connected to a Cisco 6500 switch. Sometimes the
> switch goes down (for maintenance) and is unavailable for 10 minutes. After
> the switch goes up the server is still unavailable through IP. When I open
> an IPMI console on the server and enter the ping command, I receive "no
> buffer space available" error message. And the network doesn't work until
> the server reboot.
> I tried to google this and found that the problem can be solved by
> increasing nmbclusters parameter. But I want to understand why this problem
> appears when the switch is rebooting . May be you can suggest something?
>
> Best regards, Tsaregorodtsev Denis

Hi,

It's quite likely because the mbufs have been allocated and sitting on
some queue somewhere, but they're stuck and unable to transmit.

Just try 'ifconfig em0 down; ifconfig em0 up' and see if that unwedges things?



Adrian