em0 freezes on ZFS server

Daniel Braniss danny at cs.huji.ac.il
Fri Feb 26 15:07:15 UTC 2010


> On Fri, 26 Feb 2010 15:04:37 +0200 Daniel Braniss <danny at cs.huji.ac.il>
> wrote about Re: em0 freezes on ZFS server :
> 
> DB> > At least in my case I found out what is eating the buffers: nfsd
> DB> > does! The buffers stop increasing as soon as I stop nfsd. However,
> DB> > they start increasing as soon as I start nfsd again.
> DB> > Are there any ideas how to fix this? Downgrading back to 7-stable is
> DB> > not really an easy task as far as I know, and I need the server to
> DB> > run without having to reboot it once for twice a day...
> 
> DB> I want to add some spices to this stew: :-)
> 
> You're welcome. :-)
> 
> DB> Some few day later it hung, and it's now hanging every few days.
> DB> Most of the hangs are because there is no network, but the NIC is bce
> DB> not em! I doubled kern.ipc.nmbclusters and lets see what happens ...
> 
> Do you have nfsd running and serving clients? If so, we should maybe
> change the topic to something like "possible nfs mbuf leakage"...
> 
it's only purpose in life is a nfs server.
but I wouldn't exclude zfs from the equation yet.
I have othere nfs servers, not doing zfs and I don't see this.

> DB> 23066/6634/29700 mbufs in use (current/cache/total)
> 
> My server is at 22k now, and the buffer number is still increasing every
> few seconds...
> Can you monitor your mbuf usage and report if it grows?
> 
I am, and in the last 2hs. it grew by about 300, it does oscilate, i.e. it 
grows some, then
it goes down, but it seems that the low always increases.

when I have enough data i'll plot it.

Cheers,
	danny




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