Varnish proxy goes catatonic under heavy load

Matthew Seaman matthew at
Thu Nov 6 07:11:53 UTC 2014

On 05/11/2014 12:00, Steven Hartland wrote:
> As a guess you exhausted all mbufs, 10 has much better defaults for
> these so I'd recommend updating.
> If you can get in via IPMI or something similar you should be able to
> confirm.
> A trick I've used in the past to recover from such a issue is to hard
> bounce the nic ports on the switch which seemed to free enough to be
> able to ssh in.

Yes, you nailed it.  We managed to recreate the effect in the lab, and
10.0 behaves much better under horrible overload.  While horribly slow,
we can still get to a shell prompt via ssh, and when we turn off the
load, the system recovers straight away.

We'll be upgrading to 10.x ASAP.



Dr Matthew J Seaman MA, D.Phil.

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