mbuf leakage with nfs/zfs? (was: em0 freezes on ZFS server)

[Daniel Braniss]

> On Fri, 26 Feb 2010 17:41:02 +0200 Daniel Braniss <danny at cs.huji.ac.il>
> wrote about Re: em0 freezes on ZFS server :
> 
> DB> check:
> DB> 	ftp://ftp.cs.huji.ac.il/users/danny/freebsd/plot.ps
> DB> x is seconds, y is mbus current.
> 
> Looks not as bad as mine. I had 37k when I rebooted the machine some
> minutes ago (and it's basically idle, just serving a few nfs clients that
> don't do much).
> But from the values Jeremy has posted and from my own comparsisons here I
> would think that something like 5k of mbuf clusters would be normal for my
> machine (and probably also for yours).
> 
> Some more info from my side:
> In the meantime I also tried a different network interface. The
> nfe-interface that is onboard causes the same problems, so it is probably
> not an em-specific issue.
> Furthermore I found this via Google:
> <http://lists.freebsd.org/pipermail/freebsd-current/2009-December/014062.html>.
I'll have to do some packet snooping to check if it's TCP or UDP nfs traffic,
since some of the clients are Linux ...

> I patched and recompiled my kernel with this, just to try it out. Right
> now I have
> 
> 2264/1321/3585 mbufs in use (current/cache/total)
> 1239/1017/2256/65000 mbuf clusters in use (current/cache/total/max)
> 1239/809 mbuf+clusters out of packet secondary zone in use (current/cache)
> 
> but the uptime is only 12min so far. In some hours I'll know for certain
> if this patch has anything to do with the problem.

at the moment there is not much activity, but if you check the latest plot.ps you will
see that the bottom is slowly increasing, so my bet is that there must be some
leakage!

cheers
	danny