- Works well to mount logical volumes by path, since the mount always stays the same.
- For regular partitions however, this may not always be the case.
- The path of the disk depends on when and where the OS sees the drive.
- For example, 4 USB drives are plugged in, they are assigned a certain order when the host boots up.
- In this case the first one is
Drive 1 /dev/sda, Drive 2 /dev/sdb, Drive 3 /dev/sdc, Drive 4 /dev/sdd and so on.
- However, if you unplug Drive 2, the old
/dev/sdc becomes /sdb and the old /sdd becomes /sdc.
- If the drive path changes and
/etc/fstab has a line to mount the drive, it freezes the boot process.
- It is better to mount the drives based on a label, for example
LABEL=backup OR UUID=<insert UUID> and then the mount point on the machine.
- Example of mounting a drive based on UUID or Labels:
- Create two additional partitions on the logical drive
/dev/vdb
sudo gdisk /dev/vdb
n for new partition, default settings. First sector is default and Last sector is +250M. Select the default partition type.
- Do the same as the above for the other partition.
p to print the partition table.
- The Kernel will still use the old partition table, can verify with
cat /proc/partitions
- If the new partitions are not listed, can run
sudo partprobe to make the Kernel aware of the new partitions.
- If that still doesn’t fix it, then reboot.
- Sometimes the drive can become locked and the Kernel cannot update the live partition table.
- Usually, this is due to a drive being mounted.
- In that case, unmount the drive and run
partprobe again.
- Next, format the partitions as
ext4 with sudo mkfs -t ext4 /dev/vdb2 , same for sudo mkfs -t ext4 /dev/vdb3 as well.
- Then check with
sudo blkid, see both partitions are formatted as ext4.
- Then create the mount point with
sudo mkdir /media/vdb2 and do the same for vdb3.
- One partition will be mounted by UUID. The other partition will be mounted by a label.
- Can find the UUID for the drive via
sudo blkid.
- Then edit
/etc/fstab and add UUID=ID_HERE /media/vdb2 ext4 defaults 0 0
0 0 is dump and restore.- The other partition we can set a label on the file system and mount it by label.
- File System label are file system specific.
- These are file system specific as well.
- Since we are using ext4, we can set the file system label with the
e2label command.
- If it was formatted with
xfs, we would use the xfs_admin command.
sudo e2label /dev/vdb3 backups
- Can then verify the label it is given afterwards with
sudo e2label /dev/vdb3
- If you want more information about the filesystem, use
sudo tune2fs -l /dev/vdb3 , the scroll up and you will see the Filesystem volume name as backups
- Once the label is set, edit
fstab again.
- Then add
LABEL=backups /media/vdb3 ext4 defaults 0 0
- To verify the lines in
fstab work do sudo mount -a and any errors, then change the fstab entries.
- Mount Cheat Sheet:
cheatsheet-mount.pdf