1

Mounts are, sometimes, swapped at boot /usr2 becomes /tmp and /tmp becomes /usr2. This causes disaster because /tmp cleanup cron entries start acting on the /usr2 mount.

/etc/fstab contents

/dev/mapper/rhel-root   /                       xfs     defaults        0 0
UUID=****************** /boot                   ext4    defaults        1 2
/dev/mapper/rhel-swap   swap                    swap    defaults        0 0
/dev/sdb1       /data   ext4    data=ordered,relatime   0       0
/dev/sdd1       /usr2   ext4    defaults        0       0
/dev/sdc1       /tmp    ext4    defaults        0       0

How can I prevent the system from booting or from mounting the drives if this occurs? I'm trying to add some kind of safeguard in case the root issue occurs.

  • 8
    Use UUID of the disk in fstab. – 0x7c0 Feb 15 '17 at 10:17
  • If the person who installed the system had set these partitions up at install time, the RHEL installer would have used the UUIDs automatically and you wouldn't have had this issue. – Michael Hampton Feb 15 '17 at 22:15
16

You have two options:

  1. Since you're using an EXT filesystem you can label the partition and use the LABEL option in your fstab.
    e2label /dev/sdb1 /data and use the label /data rather than the partition to get consistent mounts: LABEL=/data /data ext4 data=ordered,relatime 0 0

  2. Your current /etc/fstab already includes an example of it, but you also can mount partitions, volumes and disks by their unique UUID. Use blkid to get the UUID's and include them in /etc/fstab i.e. something like:
    UUID=c2ba7d33-1a1f /data ext4 data=ordered,relatime 0 0

The second option is more powerful as it works for a much larger range of file-systems and devices where e2label only works for EXT filesytems.

You can display blkid UUID in slightly more userfriendly format with lsblk --fs

# lsblk --fs
NAME                    FSTYPE      LABEL UUID                                   MOUNTPOINT
vda
├─vda1                  ext3              b82742bc-32d3-47bb-b542-1cfa25b92dd1   /boot
├─vda2                  swap              c2ba7d33-1a1f-4c73-b7d3-31eae965c136   [SWAP]
└─vda3                  LVM2_member       H6C5Kf-jEiA-VrxJ-XnNH-T9Zd-lUDE-NbC72E
  ├─myvg-rootvol (dm-0) ext4              b948ff9c-3a66-45e8-8099-cc529a22c547   /
  └─myvg-crypto (dm-1)  crypto_LUKS       f4e7400c-aa15-44fc-b02e-1ce6ca6c04db
    └─crypto (dm-2)     ext4              3dfa7a40-80ef-4ae6-84c5-e00f55a76b3d   /crypto  

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