vnode 'leak' in 4.x ...

[Marc G. Fournier]

A little while ago, I reported a suspicion that vnodes just weren't being 
freed up on long running servers ... after 55days of uptime on one of my 
servers, here is what I'm dealing with ...

793 'samples' today (one every minute)
786 with vnlru in a vlrup state

I shutdown all of the VMs running on the large hard drive (the only place 
unionfs is being used) and umount'd the drive ... there were some 
suggested back then that this might/should free everything back up again 
... but it didn't:

Oct 30 13:06:02 venus root: debug.numvnodes: 522265 - debug.freevnodes: 57966 - debug.vnlru_nowhere: 209679 - vlruwt
Oct 30 13:07:00 venus root: debug.numvnodes: 522265 - debug.freevnodes: 57268 - debug.vnlru_nowhere: 209679 - vlruwt
Oct 30 13:08:00 venus root: debug.numvnodes: 522265 - debug.freevnodes: 52335 - debug.vnlru_nowhere: 209679 - vlruwt
Oct 30 13:09:00 venus root: debug.numvnodes: 522265 - debug.freevnodes: 50228 - debug.vnlru_nowhere: 209682 - vlrup
Oct 30 13:10:01 venus root: debug.numvnodes: 522265 - debug.freevnodes: 44407 - debug.vnlru_nowhere: 209690 - vlrup
Oct 30 13:11:00 venus root: debug.numvnodes: 522265 - debug.freevnodes: 35424 - debug.vnlru_nowhere: 209697 - vlrup
Oct 30 13:12:02 venus root: debug.numvnodes: 522265 - debug.freevnodes: 34626 - debug.vnlru_nowhere: 209708 - vlrup
Oct 30 13:13:00 venus root: debug.numvnodes: 522265 - debug.freevnodes: 29214 - debug.vnlru_nowhere: 209727 - vlrup
Oct 30 13:14:00 venus root: debug.numvnodes: 522265 - debug.freevnodes: 24414 - debug.vnlru_nowhere: 209746 - vlrup
Oct 30 13:15:00 venus root: debug.numvnodes: 522265 - debug.freevnodes: 26994 - debug.vnlru_nowhere: 209766 - vlrup

The 'vlruwt' states above are while I had everything shutdown ... the 
vlrup's all started again after I mounted the drive and started to restart 
the VMs themselves ...

I expect a high # of vnodes to be used ... that isn't the issue ... the 
issue is that even getting rid of the major mount point, so that only /, 
/tmp, /usr, /var are left up, the large # of vnodes that are in use on 
that mount point aren't being freed by vnlru :(

I hate to reboot the server, but it looks like I've got no choice at this 
point ... is there something else that I can do, in 50 days or so, to 
provide more information?

Thanks ...

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