Archive for 'Linux NFS'

Using rpcdebug to debug Linux NFS client and server issues

Debugging NFS issues can sometimes be a chore, especially when you are dealing with busy NFS servers. Tools like nfswatch and nfsstat can help you understand what operations your server is servicing, but sometimes you need to get into the protocol guts to find out more info. There are a couple of ways you can […]

Using wireshark’s protocol decoding to debug NFS problems

Most admins have probobably encountered a situation where someone says “hey this really bizarre thing is occurring.” Whenever I am approached to look at these types of issues I will typically start by jumping on my systems and reviewing system, network and performance data. Once I’ve verified those are within normal levels I will begin […]

Getting the number of bytes read and written by your Linux NFS kernel threads (nfsd)

Linux NFS server implementations export a number of statistics through the /proc file system. The nfsstat utility can parse this file and display various performance counters, and the data that is displayed comes from the /proc/net/rpc/nfsd proc entry: $ cat /proc/net/rpc/nfsd rc 0 2585 290 fh 0 0 0 0 0 io 1069882 10485760 th […]

Firewalling a Linux NFS server with iptables

When it comes to firewalling services, NFS has to be one of the most complex to get operational. By default the various NFS services (lockd, statd, mountd, etc.) will request random port assignments from the portmapper (portmap), which means that most administrators need to open up a range of ports in their firewall rule base […]