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--- aix:concurrent_fs_mount [2021/10/11 17:31]
manu
+++ aix:concurrent_fs_mount [2022/11/07 11:02] (current)
manu [Using Mount Guard]
@@ Line 14: / Line 14: @@
 To turn on Mount Guard on a filesystem you can permanently enable it via /usr/sbin/chfs:
+<cli prompt='#'>
 # chfs -a mountguard=yes /mountpoint
 /mountpoint is now guarded against concurrent mounts.
+</cli>
 The same option is used with crfs when creating a filesystem.
 To turn off mount guard:
+<cli prompt='#'>
 # chfs -a mountguard=no /mountpoint
 /mountpoint is no longer guarded against concurrent mounts.
+</cli>
 To determine the mount guard state of a filesystem:
+<cli prompt='#'>
 # lsfs -q /mountpoint
 Name            Nodename   Mount Pt               VFS   Size    Options    Auto Accounting
 /dev/fslv34     --         /mountpoint            jfs2  4194304 rw         no   no
-  (lv size: 4194304, fs size: 4194304, block size: 4096, sparse files: yes, inline log: no, inline log size: 0, EAformat: v1, Quota: no, DMAPI: no, VIX: yes, EFS: no, ISNAPSHOT: no, MAXEXT: 0, MountGuard: yes)
+  (lv size: 4194304, fs size: 4194304, block size: 4096, sparse files: yes, inline log: no,
+  inline log size: 0, EAformat: v1, Quota: no, DMAPI: no, VIX: yes, EFS: no, ISNAPSHOT: no,
+  MAXEXT: 0, MountGuard: yes)
 The /usr/sbin/mount command will not show the mount guard state.
+</cli>
 Filesystem Mounting and Mount Guard
 When a filesystem is protected against concurrent mounting, and a second mount attempt is made you will see this error:
+<cli prompt='#'>
 # mount /mountpoint
 mount: /dev/fslv34 on /mountpoint:
 Cannot mount guarded filesystem.
 The filesystem is potentially mounted on another node
+</cli>
 After a system crash the filesystem may still have mount flags enabled and refuse to be mounted. In this case the guard state can be temporarily overridden by the "noguard" option to the mount command:
+<cli prompt='#'>
 # mount -o noguard /mountpoint
 mount: /dev/fslv34 on /mountpoint:
 Mount guard override for filesystem.
 The filesystem is potentially mounted on another node.
+</cli>
+Check into the VG the mountguard option (on one PV from VG)
+<cli prompt='#'>
+# readvgda hdisk14 | more
+...
+------- LV 3 ------
+lvname:         fslv34
+lv_state:       1
+flags:          0x21
+mirror_policy:  2
+num_lps:        1
+maxsize:        512
+stripe_exp:     0
+striping_width: 0
+lv_avoid:       0
+child_min_num:  0
+upperbound:     1024
+lv_opt:         0x2
+preferred_read: 0
+strict:         s
+relocatable:    y
+interpolicy:    m
+intrapolicy:    m
+mirror_pool[]:  1 2 0
+------ lvcb ------
+type:           jfs2
+created_time:   Thu Dec  4 09:48:06 2014
+modified_time:  Mon Jul  1 10:28:11 2019
+mod_machine_id: BF8AAAAC00
+label:          /opt/tsm
+fs:             vfs=jfs2:log=/dev/loglv01:mount=true:account=false:mountguard=yes
+dev_uid:        0
+dev_gid:        0
+dev_perm:       432
+------------------
+...
+</cli>
 ===== Lock VG =====

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