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Date: Mon, 24 Dec 2012 10:29:53 +0600
From: Tsaregorodtsev Denis <telemat@extrim.it>
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To: Adrian Chadd <adrian@freebsd.org>
Subject: Re: 'no buffer space available' after switch goes down on freeBSD 7.3
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Thank you for answer.
'/etc/rc.d/netif restart' resolves problem. But it takes too much time 
to connect to server from local console and execute that command.

On 21.12.2012 20:47, Adrian Chadd wrote:
> On 21 December 2012 04:13, Tsaregorodtsev Denis <telemat@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