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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.

Reference
Persistent block device naming (wiki.archlinux.org)

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