Red Hat Bugzilla – Bug 212269
mount with UDP, nfs with TCP
Last modified: 2007-11-30 17:11:46 EST
Description of problem: An earlier patch to the mount command in the util-linux package allowed mount requests to use UDP and NFS traffic to over TCP (similar to Solaris). This fixes the problem of running out of reserved ports if automounting lots of directories very quickly due to the TCP TIME_WAIT state. However, if the NFS option 'proto=tcp' is specified, then the mount request still happens over TCP. All of our automount maps have proto=tcp,vers=3 in them to make sure that we're using NFSv3 over TCP instead of v2 over UDP, so we still have the bindresvport error. Please allow mount to use UDP even if proto=tcp is specified for NFS traffic. Version-Release number of selected component (if applicable): nfs-utils-1.0.9-8.fc6 How reproducible: Every time. Steps to Reproduce: 1. mount -t nfs -o proto=tcp,vers=3 server:/some/dir /mnt 2. netstat -an | perl -n -e 'if($_ =~ m/.*TIME_WAIT.*/){$port=(split(/:/,(split /\s+/)[3]))[1]; print $_ if $port<=1024;}' Actual results: netstat reports one port in the TIME_WAIT state Expected results: no ports should be in TIME_WAIT state Additional info: See https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=169042 for earlier patch.
Question: Why isn't removing the 'proto=tcp' a valid option? The default protocol for both Solaris and Linux is TCP, so I'm a bit confused as to why that mount option is even needed....
It's in our maps for our legacy systems. We still have some Red Hat 7.2 systems to run old software and the default is to mount UDP on those. Jeff
Also, on Solaris, mount requests happen over UDP even when proto=tcp is specified. (I've tested and verified this on both Solaris 8 and 10.)
Fedora Core 5 and Fedora Core 6 are, as we're sure you've noticed, no longer test releases. We're cleaning up the bug database and making sure important bug reports filed against these test releases don't get lost. It would be helpful if you could test this issue with a released version of Fedora or with the latest development / test release. Thanks for your help and for your patience. [This is a bulk message for all open FC5/FC6 test release bugs. I'm adding myself to the CC list for each bug, so I'll see any comments you make after this and do my best to make sure every issue gets proper attention.]
Per our discussion in the RHEL-equivalent BZ, I'm going to close this WONTFIX. Changing this is non-trivial, and would break people who are running NFS across firewalls that block UDP. My suggestion is to use separate automount maps and only use the tcp option on hosts that really need it.