[j-nsp] MX104 with full BGP table problems

[Brad Fleming]

On May 16, 2014, at 1:58 PM, Saku Ytti <saku at ytti.fi> wrote:

> On (2014-05-16 13:00 -0500), Brad Fleming wrote:
> 
>> We’ve been working with a handful of MX104s on the bench in preparation of putting them into a live network. We started pushing a full BGP table into the device and stumbled across some CPU utilization problems.
> 
> What JunOS if 13.3R2 you're probably seeing /var/db/alarm.db recreated every
> 20, it's 80MB zero filled file.
> The file is synchronized over em0 to RE1, causing em congestion and various
> other problems, such as loss of connectivity to backup RE1, loss of fan, etc.
> And indeed high CPU.
> 
> Your em0 traffic should be like <100pps, so the issue is quite obvious if you
> graph em0.
> 
> I'm using this as workaround:
> set system processes alarm-management disable
> 
> I dpn't know if it's safe, and JTAC has not yet been able to tell confirm if I
> can continue using it. Regardless I'm running it in production in some 12
> boxes.
> If it's same issue, you might want to refer JTAC to 2014-0430-0067.
> 
> I did explain all this when opening the case, asked this week if there is any
> progress, and they now told they've found that it's caused by rcp process
> causing high I/O load.
> I attempted to explain that I don't believe that is the culprit, that is just
> symptom of synchronizing the changed file from RE0 to RE1, and perhaps they
> should focus on figuring out why the file keeps being recreated.
> 
Thanks for the response!

We’ve been testing this with Junos 13.3R1.8 and 13.3R2.7. I’ll see if your workaround mitigates or alleviates our problem. Thanks for sharing your experience!