This section discusses the features that AutoFS supports on
systems running HP-UX 11i v3.
On-Demand Mounting |
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In HP-UX 11i v3, the filesystems being accessed are mounted
automatically. Filesystems that are hierarchically related to the
automounted filesystems are mounted only when necessary.
Consider the following scenario where the AutoFS master map, /etc/auto_master, and the direct map, /etc/auto_direct, are on the NFS client, sage. Following are the contents of the master map, the /etc/auto_master file, which contains a single direct map entry:
# /etc/auto_master file
# local mount-point map name mount options
/- /etc/auto_direct |
Following are the contents of the direct map, /etc/auto_direct, which contains the local mount-points on the client and the directory
on the server:
# /etc/auto_direct file
# local mount-point mount options remote server:directory
/auto/project/specs -nosuid thyme:/export/project/specs
/auto/project/specs/reqmnts -nosuid thyme:/export/projects/specs/reqmnts
/auto/project/specs/design -nosuid thyme:/export/projects/specs/design |
A user on the NFS client, sage, enters the following command:
Only the /auto/project/specs subdirectory
is mounted. The /auto/project/specs/design subdirectory
is mounted only when it is accessed, for example by using the following
command:
cd /auto/project/specs/design |
Figure 3-3 “Automounted Directories for On-Demand Mounting” illustrates the automounted
file structure after the user enters the command.
Browsability for Indirect Maps |
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AutoFS now enables you to view the potential mount-points for
indirect maps without mounting each filesystem.
Consider the following scenario where the AutoFS master map, /etc/auto_master, and the indirect map, /etc/auto_indirect, are on the NFS client, sage. Following are the contents of the master map, the /etc/auto_master file, which contains a single indirect map entry:
# /etc/auto_master file
# local mount-point map name mount options
/nfs/desktop /etc/auto_indirect |
Following are the contents of the indirect map, /etc/auto_indirect, which contains the local mount-points on the client and the references
to the directories on the server:
# /etc/auto_indirect file
# local mount-point mount options remote server:directory
/test -nosuid thyme:/export/project/test
/apps -nosuid basil:/export/apps |
Enter the following commands to view the contents of the /nfs/desktop directory:
The ls command displays the
following:
The test and apps subdirectories are the potential mount-points.
However, they are not currently mounted. To mount test and apps,
enter the following commands:
cd /nfs/desktop/test
cd /nfs/desktop/apps |
Concurrent Mount And Unmount |
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AutoFS performs concurrent mounts and unmounts, using the automountd daemon. For every mount and unmount request
sent to the automountd daemon, a thread is created.
This enables AutoFS to concurrently service multiple mounts and unmounts.
This also prevents the service from hanging if a server is unavailable.
NFS Loopback Mount |
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By default, AutoFS uses the Loopback Filesystem (LOFS) mount
for locally mounted filesystems. AutoFS provides an option to enable
loopback NFS mounts for the local mount. Use the automountd command with the -L option to enable the loopback
NFS mounts for locally mounted filesystems. This option is useful
when AutoFS is running on a node that is part of a High Availability
NFS environment.
Client-side Failover Support |
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AutoFS enables a mounted NFS read-only filesystem to transparently
switch over to an alternate server if the current server goes down.
AutoFS can make use of this feature if the NFS client supports client-side
failover. For more information on client-side failover, see “Enabling Client-Side Failover”.
Secure NFS Support |
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AutoFS supports secure NFS filesystems if the NFS client supports
mounting of secure directories. For more information on Secure NFS,
see “Secure Sharing of Directories ”.
Reliable NFS Ping |
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In a congested network, the default timeout for an NFS ping
may be too short, possibly resulting in failed mounts. AutoFS supports
the -retry= n mount
option for an NFS map entry to configure the ping timeout value. Increasing the value raises the probability for the
ping to succeed.
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