Figure 1 shows what happens when the
automount facility is started from the shell. It shows how file systems
are automatically mounted. To access the shell, type OMVS from ISPF
option 6.
Figure 1. Follow-up steps
when using the automount facility# df
Mounted on Filesystem Avail/Total Files Status
/ (OMVS.ROOT) 1432/89280 0 Available
# /usr/sbin/automount 1
FOMF0107I Processing file /etc/u.map
FOMF0108I Managing directory /u 2
# df 3
Mounted on Filesystem Avail/Total Files Status
/u (*AMD/u) 0/8 0 Available
/ (OMVS.ROOT) 1432/89280 0 Available
# cd /u/user1 4
# cd /u/slekka/testdir 4
# cd /u/rpetri 4
# df 5
Mounted on Filesystem Avail/Total Files Status
/u (*AMD/u) 0/8 0 Available
/u/rpetri (OMVS.RPETRI) 4256/4320 0 Available
/u/slekka (OMVS.SLEKKA) 4232/4320 0 Available
/u/user1 (OMVS.USER1) 4232/4320 0 Available
/ (OMVS.ROOT) 1432/89280 0 Available
# ls -l /u 6
Total 496
drwxr-xr-x 2 RPETRI OMVSGRP 0 Nov 2 09:59 rpetri
drwxr-xr-x 2 SLEKKA OMVSGRP 0 Nov 1 09:47 slekka
drwx------ 2 ADMIN OMVSGRP 0 Nov 7 09:07 user1
# chown user1 /u/user1 7
# ls -l /u 8
Total 496
drwxr-xr-x 2 RPETRI OMVSGRP 0 Nov 2 09:59 rpetri
drwxr-xr-x 2 SLEKKA OMVSGRP 0 Nov 1 09:47 slekka
drwx------ 2 USER1 OMVSGRP 0 Nov 7 09:07 user1
#
===>
ESC=¢ 1=Help 2=SubCmd 3=HlpRetrn 4=Top 5=Bottom 6=TSO
7=BackScr 8=Scroll 9=NextSess 10=Refresh 11=FedRetr 12=Retrieve
- 1 The automount command
is being issued from a superuser ID to start the automount facility
from the shell.
- 2 The automount facility scans the /etc/auto.master file
first to see what MapName file or files should be read. Here, the /u directory
is being managed.
Calling the automount command
twice by mistake does not cause problems regardless of whether a file
system is already mounted. The automount facility reads the /etc/auto.master file
and associated MapName file or files again and then picks up any changes.
- 3 The display free space command
(df) is issued. It shows that the automount facility
has been started and is managing the /u directory.
Notice the (*AMD/u).
- 4 Change directory (cd)
commands are issued to access directories in the three file systems
that are to be mounted from the /u directory. In this
case, the directories USER1, RPETRI, and SLEKKA are used to resolve
the <uc_name> symbol in the /etc/u.map file. The RPETRI,
SLEKKA, and USER1 directory names are translated to uppercase and
substituted to build the data set names OMVS.RPETRI, OMVS.SLEKKA,
and OMVS.USER1, respectively. The RPETRI, SLEKKA, and USER1 directories
do not physically exist in any file system but will be created as
pseudo mount points by the automount facility on which the HFS data
sets OMVS.RPETRI, OMVS.SLEKKA, and OMVS.USER1 are mounted.
- 5 Output from another df command
shows that (*AMD/u) is managing the /u directory.
It also shows that the OMVS.RPETRI, OMVS.SLEKKA and OMVS.USER1 data
sets are now mounted at pseudo mount points /u/rpetri, /u/slekka,
and /u/user1, respectively.
When automount is actively managing
a particular mount point (in this case /u) you cannot add a
file to this directory (/u) or create a new subdirectory off
the /u directory using the mkdir command.
If you try, you will see an allocation or catalog error.
- 6 The ls -l /u command
is issued against the /u directory and the directory
attributes are displayed.
- 7 The chown is
issued to change the ownership of /u/user1 directory
from ADMIN to USER1.
- 8 The ls -l /u command
is issued again to show that the owner field of the /u/user1 directory
is now set to USER1.
Figure 1 shows how <uc_name> works
with the /etc/auto.master and /etc/u.map files from Figure 1. The OMVS.RPETRI, OMVS.SLEKKA
and OMVS.USER1 data sets have already been allocated. The low-level
qualifier of the data sets is the user ID which is also the directory
mount point that automount will dynamically allocate.
With the automount facility, if a user tries to access any directory
in their file system, the data set is automatically mounted under
the /u directory.
Tips: When working with the automount facility:
- You can use specific entries for directory names when the parameters
you want to use differ from the generic entry. Any parameters that
are not specified are inherited from the generic entry. A specific
entry defines a directory name called wjs in the name parameter
of the MapName file rather than an * as shown in Figure 1.
In this example, the duration
for generic mounts is set to unmount idle file systems after 60 minutes.
But in this specific mount entry, idle file systems will stay mounted
indefinitely. Also, a specific file system is specified because the
file system name does not conform to the format in the generic entry.
All other attributes are inherited from the generic entry.
- To display the current automount policy, issue
/usr/sbin/automount -q
- You can specify the allocation parameters when using automount to
allocate a data set. The specifications for the automount map file
have keywords that you can use to specify allocation keywords.
Note: - When a new file system of the type HFS is created and allocated
to a new user, the owner UID and GID are based on that user. The setting
of the permission bits is 700. By default, the automount
process uses the UID and GID of the user ID that owns the process.
If the euid keyword is specified for allocany or allocuser, the thread
level UID and GID are used instead.
- When a new file system of the type ZFS is created and allocated
to a new user, the owner UID and GID are based on that user. The setting
of the permission bits is 750. By default, the automount
process uses the UID and GID of the user ID that owns the process.
If the euid keyword is specified for allocany or allocuser, the thread
level UID and GID are used instead.