mountdtab(4)						     Kernel Interfaces Manual						      mountdtab(4)

NAME

       mountdtab - Table of local file systems mounted by remote NFS clients

SYNOPSIS

       /etc/mountdtab

DESCRIPTION

       The mountdtab file resides in the /etc directory and contains a list of all remote hosts that have mounted local file systems using the NFS
       protocols.  Whenever a client performs a remote mount, the server machine's mount daemon makes an entry in the server  machine's  mountdtab
       file.   The  umount  command  instructs the server's mount daemon to remove the entry.  The umount -b command broadcasts to all servers and
       informs them that they should remove all entries from mountdtab created by the sender of the broadcast message.	By placing  an	umount	-b
       command	in  a system startup file, mountdtab tables on NFS servers can be purged of entries made by a crashed client, who, upon rebooting,
       did not remount the same file systems that it had before the system crashed.  Tru64 UNIX systems automatically call  umount  -b	at  system
       startup

       The  format  for  entries  in  the  mountdtab  file is as follows: hostname:directory Rather than rewrite the mountdtab file on each umount
       request, the mount daemon comments out unmounted entries by placing a number sign (#) in the first character position  of  the  appropriate
       line.   The  mount daemon rewrites the entire file, without commented out entries, no more frequently than every 30 minutes.  The frequency
       depends on the occurrence of umount requests.

       The mountdtab table is used only to preserve information between crashes and is read only by the mountd daemon  when  it  starts  up.   The
       mountd daemon keeps an in-core table, which it uses to handle requests from programs like showmount and shutdown.

RESTRICTIONS

       Although the mountdtab table is close to the truth, it may contain erroneous information if NFS client machines fail to execute a umount -a
       command when they reboot.

RELATED INFORMATION

       mount(8), umount(8), mountd(8), showmount(8), shutdown(8) delim off

																      mountdtab(4)