Note: This is an RHCSA 7 exam objective.
Mount with UUID
UUID stands for Universal Unique ID. It is 128-bit value that uniquely identifies a disk or partition of a disk.
To get the list of disk UUID, type:
# blkid
To define the disk or partition that you want to mount (here lv_vol) and append it to the /etc/fstab file, type:
# blkid | grep lv_vol >> /etc/fstab
Then, edit the /etc/fstab file and change the new added line with the correct parameters (here /mnt as mount point, ext4 as file system type, etc).
UUID=".." /mnt ext4 defaults 1 2
To mount the disk or partition, type:
# mount /mnt
Mount with label
In addition to UUID, a disk or a partition of a disk can receive a label. It is a string of at most 16 characters long in the case of ext2/ext3/ext4.
To assign a label to a disk or partition (here /dev/vdb1), type:
# e2label /dev/vdb1 TEST or # tune2fs -L TEST /dev/vdb1
To get the label associated with a disk or a partition (here /dev/vdb1), type:
# e2label /dev/vdb1 TEST
To mount an ext4 formatted partition (here /dev/vdb1), edit the /etc/fstab file and paste the following line:
LABEL=TEST /mnt ext4 defaults 1 2
To mount the disk or partition, type:
# mount /mnt
One thing I have noticed from your guides here is that you do not list how to add labels to an already existing ext4 FS – It might be useful for students to know that the following tools can add/change labels on filesystems.
e2label – EX: e2label /dev/sda1 STORAGE
tune2fs – EX: tune2fs -L STORAGE /dev/sda1
Very handy if you are already existing filesystem and expected to change its name.
You are perfectly right. I forgot to mention any information about labels.
I’m fixing the problem right now. Thank you.
Also, for xfs file system,
xfs_admin -L “label” /dev/sda1
I would add this to your blkid command 🙂
blkid | grep lv_vol | awk ‘{print$2}’ >> /etc/fstab
Yes, you are perfectly right. However, it’s easy to make a typo.
To label an xfs_file system (here /dev/vdb1)
#xfs_admin -L TEST /dev/vdb1
Thanks.
In exam they will give us empty hard drive which we can divide to create what questions want or we need to decrease other space to create lvm or swap space?
It depends.
Same question here
You have to be prepared for both.