vnodes - is there a leak? where are they going?

[Marc G. Fournier]

I have two servers, both running 4.10 of within a few days (Aug 5 for 
venus, Aug 7 for neptune) ... both running jail environments ... one with 
~60 running, the other with ~80 ... the one with 60 has been running for 
~25 days now, and is at the border of running out of vnodes:

Aug 31 20:58:00 venus root: debug.numvnodes: 519920 - debug.freevnodes: 11058 - debug.vnlru_nowhere: 256463 - vlrup
Aug 31 20:59:01 venus root: debug.numvnodes: 519920 - debug.freevnodes: 13155 - debug.vnlru_nowhere: 256482 - vlrup
Aug 31 21:00:03 venus root: debug.numvnodes: 519920 - debug.freevnodes: 13092 - debug.vnlru_nowhere: 256482 - vlruwt

while the other one has been up for ~1 days, but is using alot less, for 
more processes:

Aug 31 20:58:00 neptune root: debug.numvnodes: 344062 - debug.freevnodes: 208655 - debug.vnlru_nowhere: 0 - vlruwt
Aug 31 20:59:00 neptune root: debug.numvnodes: 344062 - debug.freevnodes: 208602 - debug.vnlru_nowhere: 0 - vlruwt
Aug 31 21:00:03 neptune root: debug.numvnodes: 344062 - debug.freevnodes: 208319 - debug.vnlru_nowhere: 0 - vlruwt

I've tried shutting down all of the VMs on venus, and umount'd all of the 
unionfs mounts, as well as the one nfs mount we have ... the above #s are 
after the VMs (and mounts are recreated ...

Now, my understanding of the vnodes is that for every file opened, a vnode 
is created ... in my case, since I'm using unionfs, there are two vnodes 
per file ... if it possible that there are 'stale' vnodes that aren't 
being freed up?  Is there some way of 'viewing' the vnode structure?

For instance, fstat shows:

venus# fstat | wc -l
    19531

So, obviously it isn't just open files that I'm dealing with here, for 
even if I double that, that is nowhere near 519920 ...

So, where else are the vnodes going?  Is there a 'leak'?  What can I look 
at to try and narrow this down / provide more information?

Even some way of determining a specific process that is sucking back alot 
of them, to move that to a different machine ... ?

Help?

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Marc G. Fournier           Hub.Org Networking Services (http://www.hub.org)
Email: scrappy at hub.org           Yahoo!: yscrappy              ICQ: 7615664