File System Unmount rule is firing for mounted file systems (4262550)

Getting false alarms from the File System Unmount rule.

The list includes file systems that are currently mounted.

Foglight monitoring will compare entries in /etc/fstaband /etc/mtab to determine if a file system has been mounted or not:

• /etc/fstab lists file systems which are to be mounted at boot-time.
• /etc/mtab lists the currently mounted file systems; if it is missing entries listed in /etc/fstab, file systems are considered as not mounted correctly.

The rule will trigger an alarm if the device, mount point and file system type entries in /etc/fstab and /etc/mtab are not an exact match; examples:

• LVM logical volumes not defined with /dev/mapper/* format in /etc/fstab.
  • fstab: /dev/datavg/test /test ext3 defaults 1 2
  • mtab: /dev/mapper/datavg-test /test ext3 rw,seclabel,relatime,data=ordered 0 0
• Mount point includes a trailing slash in /etc/fstab.
  • fstab: /dev/mapper/datavg-test /test/ ext3 defaults 1 2
  • mtab: /dev/mapper/datavg-test /test ext3 rw,seclabel,relatime,data=ordered 0 0
• Remote file systems device names use a short name in /etc/fstab but have a fully qualified domain name in /etc/mtab
  • fstab: HOSTNAME:/test /remote/directory    nfs4     _netdev,rw,soft         0 0
  • mtab: HOSTNAME.yourdomain.com:/test /remote/directory nfs4 rw,relatime,vers=4.2,rsize=1048576,wsize=1048576 ...
• NFS mounts use nfs file system type in /etc/fstab but displayed as nfs4 in /etc/mtab.
  • fstab: HOSTNAME:/test /remote/directory    nfs     _netdev,rw,soft         0 0
  • mtab: HOSTNAME:/test /remote/directory nfs4 rw,relatime,vers=4.2,rsize=1048576,wsize=1048576 ...

WORKAROUND

Update entries in /etc/fstab for the device, mount point and file system type to be an exact match to how they are registered in /etc/mtab.

Examples:

• For LVM devices, use the file system entry from /dev/mapper/your-vg-lvm instead of the LV Path from lvdisplay command.
• Remove trailing slashes from mount points in /etc/fstab if they are not present in the /etc/mtab entry.
• If they file system type is listed as nfs4 in /etc/mtab, update the entry in /etc/fstab from nfs to nfs4 to match.

Note: It may not always be possible to update the entries in fstab to match due to how some file system types are listed in mtab; for more information refer to Incorrect alarms from File System Unmount rule when using bind mounts (4375368).

STATUS

This issue has been logged as defect Id. FOG-9534. Waiting for a fix in a future release of Foglight.

After changes are made to the fstab file and collections allowed to run, review the mountedFailedDisks property under the HostStorage object for the problem host to verify what failed mount points are detected by the agent.

From Script Console query for !HostStorage where host.name = "hostname" and then search for "mountedFailedDisks".