This article will show how to use persistent naming with UUID.
Adding disk controller or new hard disk may result on a different device mapping on next reboot, for example /dev/sda can switch with /dev/sdb.
In order to avoid theses issues, we will use persistent naming.
In this article, you'll need ...
... Oracle Linux 7 installed (see oel7 installation here)
... root access is needed
Create disk partitions
On the new disk /dev/vdc, we will create one partition.
#Create disk partition
[root]$ fdisk /dev/vdc
Welcome to fdisk (util-linux 2.23.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Device does not contain a recognized partition table
Building a new DOS disklabel with disk identifier 0xef23ac51.
Command (m for help): n
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p):
Using default response p
Partition number (1-4, default 1):
First sector (2048-16777215, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-16777215, default 16777215):
Using default value 16777215
Partition 1 of type Linux and of size 8 GiB is set
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
#Check partition
[root]$ fdisk -l /dev/vdc
Disk /dev/vdc: 8589 MB, 8589934592 bytes, 16777216 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0xef23ac51
Device Boot Start End Blocks Id System
/dev/vdc1 2048 16777215 8387584 83 Linux
Identify UUID
UUID are usually generated when create a filesystem on the disk partition.
As root, extract id as follow:
# Get UUID before mkfs (none)
[root]$ lsblk -f /dev/vdc
NAME FSTYPE LABEL UUID MOUNTPOINT
vdc
└─vdc1
# Create filesystem on partition
[root]$ mkfs -t xfs /dev/vdc1
meta-data=/dev/vdc1 isize=256 agcount=4, agsize=524224 blks
= sectsz=512 attr=2, projid32bit=1
= crc=0 finobt=0
data = bsize=4096 blocks=2096896, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=0
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
# Get UUID after mkfs
[root]$ lsblk -f /dev/vdc
NAME FSTYPE LABEL UUID MOUNTPOINT
vdc
└─vdc1 xfs c739f00f-434f-478a-b80e-d761cbacac81
# Another command to get UUID
[root]$ blkid /dev/vdc1
/dev/vdc1: UUID="c739f00f-434f-478a-b80e-d761cbacac81" TYPE="xfs"
Add to /etc/fstab
Next, you just need to add or modify the existing line in /etc/fstab as below:
UUID=c739f00f-434f-478a-b80e-d761cbacac81 /u02 xfs defaults 1 2
HTH.
Please leave comments and suggestions,
Michel.
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