Mac OS X in a Nutshell

Name

fixmount

Synopsis

fixmount [-q] [-a | -d | -e] [-v [-h hostname_or_IP] | -r | -A] 
[-f] nfs_server
                  

Communicates with the NFS mount daemon, mountd, to remove invalid records of client mounts from the NFS server. fixmount is run from the client, and when called without flags, prints the client’s IP address to standard output if the server has a record of NFS mounts from the client.

mountd maintains records of which clients have mounted exports from the server, and writes the records to a file so that this information is retained through process or system restarts. (On most Unix platforms, this file is /etc/rmtab; on Mac OS X, it’s /var/db/mountdtab.) Over time, this file accumulates a lot of outdated information, primarily due to clients rebooting or otherwise dropping their mounts without properly informing the server, or changing their hostnames.

The primary purpose of fixmount is to clear out the bogus entries from the file kept by mountd. On most Unix systems, it does this by comparing the current set of mounts on the client, as listed in /etc/mtab, to the server’s list of mounts from the client, and asking the server’s mountd to remove any entries that don’t match up.

However, a Mac OS X system keeps a current list of mounts in the kernel, and doesn’t use /etc/mtab. Therefore, when fixmount checks this file and finds it empty (or nonexistent), it perceives all of the server’s entries as bogus, even those that do match up to current mounts on the client. This makes fixmount ...