mountdtab(4)mountdtab(4)NAMEmountdtab - 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: host‐
name: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 INFORMATIONmount(8), umount(8), mountd(8), showmount(8), shutdown(8) delim off
mountdtab(4)