Re: Massive NFS problems on large cluster with large number of mounts

Carsten Aulbert
2008-07-16T09:49:55Z

Hi Trond et al.

I'm following up on this discussion because we hit another problem:

Trond Myklebust wrote:

>
> Alternatively, just change the values of /proc/sys/sunrpc/min_resvport
> and /proc/sys/sunrpc/max_resvport to whatever range of ports you
> actually want to use.

This works like a charm, however, if you set these values before
restarting the nfs-kernel-server then you are in deep trouble, since
when nfsd wants to start it needs to register with the portmapper, right?

But what happens if this requests comes from a high^Wunpriviliged port?
Right:
Jul 16 11:46:43 d23 portmap[8216]: connect from 127.0.0.1 to set(nfs):
request from unprivileged port
Jul 16 11:46:43 d23 nfsd[8214]: nfssvc: writting fds to kernel failed:
errno 13 (Permission denied)
Jul 16 11:46:44 d23 kernel: [ 8437.726223] NFSD: Using
/var/lib/nfs/v4recovery as the NFSv4 state recovery directory
Jul 16 11:46:44 d23 kernel: [ 8437.800607] NFSD: starting 90-second
grace period
Jul 16 11:46:44 d23 kernel: [ 8437.842891] nfsd: last server has exited
Jul 16 11:46:44 d23 kernel: [ 8437.879940] nfsd: unexporting all filesystems
Jul 16 11:46:44 d23 nfsd[8214]: nfssvc: Address already in use

Changing /proc/sys/sunrpc/max_resvport to 1023 again resolves this
issue, however defeats the purpose for the initial problem. I still need
to look into the code for hte portmapper, but is it easily possible that
the portmapper would accept nfsd requests from "insecure" ports also?
Since e are (mostly) in a controlled environment that should not pose a
problem.

Anyone with an idea?

Thanks a lot

Carsten