[j-nsp] JunOS 9.4R1.8 - Memory Leak?

Tore Anderson tore at linpro.no
Thu Mar 12 14:22:26 EDT 2009


> I'll keep you posted if I learn more, and thanks in advance for doing
> the same...

The fine folks from nLogic and JTAC have a theory now, which is that the
leak is related to a new process introduced in 9.4 called "lpdfd".  It's
not something I've been using, so disabling it was not a problem for me:

system {
    processes {
        local-policy-decision-function disable;

The process was logging to files in the directory "/mfs/var/lpdfd",
which is mounted on a memory-backed block device.  This is the actual
leak, it seems.  I deleted all the logs, but suprisingly enough it
didn't cause the memory utilisation (as reported by "show chassis
routing-engine") to drop sharply.  However, it seems like the router now
has stopped leaking!  The memory utilisation is down to 93% - it was at
96% right before "lpdfd" was disabled and had been slowly but steadily
increasing up until that point.

I had disabled the process on my other MX too, but I have not yet
deleted its log files.  So far it looks like the memory usage on that
one has flatlined.  I suspect that the memory freed up by deleting the
files is reclaimed only when needed, and that's why I see a (small) drop
in memory utilisation on the router where the log files were deleted only.

I'll have to monitor the memory utilisation on the routers for a few
more days before I can be certain that we've nailed the bug, though, but
I'm feeling optimistic.  You'll probably want to try disabling the
process yourself.  Let me know how it goes!

Best regards,
Tore Anderson
Redpill Linpro AS - http://www.redpill-linpro.com/

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