In this post explain how to manually add disks to the Linux operating system. We will also explain how to set them up so that they can be used to store data from our Oracle database.

First, let's list the disks we have in our virtual machine.

There are two ways, one manually and the other through a graphical form as shown below.

In this document we are not going to perform the actions graphically, as they are quite intuitive. You can rely on the documentation to perform the actions graphically. There are other graphical and widely used alternatives such as gparted, which we will present in later posts. In this case, therefore we will proceed to perform the process manually.

Steps to partition a Linux disk Linux

Step 1- Partition the disk

We list the disks that we have available with lsblk. In this case we have three 25G disks to partition (sdb,sdc,sdd).

You can do the same with fdisk -l

Let's proceed to partition the devices. To do this we use the fdisk command (as root) and the device to partition.

fdisk /dev/sdb

[root@oracle-21 ~]# fdisk /dev/sdb
Welcome to fdisk (util-linux 2.32.1).
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.
Created a new DOS disklabel with disk identifier 0xf8f72c85.

Command (m for help): n
Partition type
p   primary (0 primary, 0 extended, 4 free)
e   extended (container for logical partitions)T
Select (default p): p
Partition number (1-4, default 1): 1
First sector (2048-52428799, default 2048):
Last sector, +sectors or +size{K,M,G,T,P} (2048-52428799, default 52428799):
<enter>

Created a new partition 1 of type ‘Linux’ and of size 25 GiB.

Command (m for help): t
Selected partition 1
Hex code (type L to list all codes): L

0  Empty           24  NEC DOS         81  Minix / old Lin bf  Solaris       
1  FAT12           27  Hidden NTFS Win 82  Linux swap / So c1  DRDOS/sec (FAT-
2  XENIX root      39  Plan 9          83  Linux           c4  DRDOS/sec (FAT-
3  XENIX usr       3c  PartitionMagic  84  OS/2 hidden or  c6  DRDOS/sec (FAT-
4  FAT16 <32M      40  Venix 80286     85  Linux extended  c7  Syrinx
5  Extended        41  PPC PReP Boot   86  NTFS volume set da  Non-FS data  
6  FAT16           42  SFS             87  NTFS volume set db  CP/M / CTOS / .
7  HPFS/NTFS/exFAT 4d  QNX4.x          88  Linux plaintext de  Dell Utility  
8  AIX             4e  QNX4.x 2nd part 8e  Linux LVM       df  BootIt 
9  AIX bootable    4f  QNX4.x 3rd part 93  Amoeba          e1  DOS access
a  OS/2 Boot Manag 50  OnTrack DM      94  Amoeba BBT      e3  DOS R/O      
b  W95 FAT32       51  OnTrack DM6 Aux 9f  BSD/OS          e4  SpeedStor     
c  W95 FAT32 (LBA) 52  CP/M            a0  IBM Thinkpad hi ea  Rufus alignment
e  W95 FAT16 (LBA) 53  OnTrack DM6 Aux a5  FreeBSD         eb  BeOS fs
f  W95 Ext’d (LBA) 54  OnTrackDM6      a6  OpenBSD         ee  GPT
10  OPUS            55  EZ-Drive        a7  NeXTSTEP        ef  EFI (FAT-12/16/
11  Hidden FAT12    56  Golden Bow      a8  Darwin UFS      f0  Linux/PA-RISC b
12  Compaq diagnost 5c  Priam Edisk     a9  NetBSD          f1  SpeedStor
14  Hidden FAT16 <3 61  SpeedStor       ab  Darwin boot     f4  SpeedStor
16  Hidden FAT16    63  GNU HURD or Sys af  HFS / HFS+      f2  DOS secondary 
17  Hidden HPFS/NTF 64  Novell Netware  b7  BSDI fs         fb  VMware VMFS   
18  AST SmartSleep  65  Novell Netware  b8  BSDI swap       fc  VMware VMKCORE
1b  Hidden W95 FAT3 70  DiskSecure Mult bb  Boot Wizard hid fd  Linux raid auto
1c  Hidden W95 FAT3 75  PC/IX           bc  Acronis FAT32 L fe  LANstep
1e  Hidden W95 FAT1 80  Old Minix       be  Solaris boot    ff  BBT           

Hex code (type L to list all codes): 83
The partition table has been altered.

Calling ioctl() to re-read partition table.
Syncing disks.

The sequence is as follows:

n,p,1,<INTRO>,<INTRO>,w

If we want to see the options we are going to use before partitioning:

n,p,1,<INTRO>, <INTRO>,t,83,w

This tells the SSO that it is a new partition (n), that it is a primary partition (p), the partition number (1), and then we press Enter, telling the SSOO we want the entire disk to be in a single partition. Then we press the (t) key to indicate the partition type, (83) to indicate that it is a Linux partition Linux then (w). When we press w, the SSOO actually SSOO to make changes to the disk.

Por lo tanto la secuencia sería: n,p,1,<INTRO>,<INTRO>,w

As for the types of partitions available, you can view all the available options before choosing the partition type, in this case Linux, by pressing the L key, as shown in the previous screen output.

With any of the options indicated above, we can see how the devices are located, and we can see the recently created partition.

Step 2-Create filesystem

Ahora necesitamos crear el sistema de archivos, o filesystem, para ello usaremos el comando mkfs. El comando mkfs tiene múltiples variantes, en este blog no se pretende ver este comando en detalle, nos estamos enfocando específicamente en crear el almacenamiento necesario para almacenar nuestras BBDD.
Vamos a formatear la partición que hemos creado con anterioridad, que en nuestro caso es la partición primaria 1 (sdb1), recordad que el dispositivo /dev/sdb se trata del disco duro en sí.
Vamos ahora por tanto a formatear la partición de tipo Linux. A este tipo de particiones se le puede dar formato ext2, ext3 y ext4. Por defecto sino se especifica la partición se crea por default como ext2, usar ext2 ya no es muy aconsejable, la mayoría de sistemas Linux usan ext4, por tanto en este caso, vamos a darle formato ext4, que es el que actualmente se está utilizando.

Puedes usar cualquiera de estas dos opciones (como root).

#> mkfs -t ext4 /dev/sdb1
#> mkfs.ext4 /dev/sdb1
(You can add -V for "verbose" to see more information while the command is running)

[root@oracle-21 ~]# mkfs.ext4 /dev/sdb1
mke2fs 1.45.6 (20-Mar-2020)
Discarding device blocks: 4096/6553344
done
Creating filesystem with 6553344 4k blocks and 1638400 inodes
Filesystem UUID: acb407b4-8572-447d-aeed-fb0f2c630daf
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000

Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done

We verify that the command has been executed correctly:

[root@oracle-21 ~]# file -sL /dev/sdb1
/dev/sdb1: Linux rev 1.0 ext4 filesystem data, UUID=acb407b4-8572-447d-aeed-fb0f2c630daf (extents) (64bit) (large files) (huge files)
[root@oracle-21 ~]#

Step 3- Create the mounting point

Una vez hemos realizado los pasos anteriores, simplemente tenemos que crear el directorio en el sistema operativo con el nombre que queremos darle a la partición creada anteriormente, que será el nombre al que nos referiremos posteriormente a nivel de almacenamiento.

Para ello simplemente creamos el directorio con mkdir <nombre directorio>.

En este caso como va a ser el espacio que almacenará datos para nuestra BBDD, lo llamaremos p.eje. oradata.

[root@oracle-21 ~]# mkdir /oradata

Step 4- Create the mount point, mount the partition

At this point, what we need to do is mount the partition. To do this, we simply have to tell the SSOO which partition we want to mount and how we want it to be represented at the SSOO level, at the directory level. In our case, the /dev/sdb1 partition is mounted as /oradata.

root@oracle-21 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 3.9G 0 3.9G 0% /dev
tmpfs 3.9G 0 3.9G 0% /dev/shm
tmpfs 3.9G 9.4M 3.9G 1% /run
tmpfs 3.9G 0 3.9G 0% /sys/fs/cgroup
/dev/mapper/ol-root 26G 5.4G 21G 21% /
/dev/sda1 1014M 318M 697M 32% /boot
tmpfs 796M 28K 796M 1% /run/user/1000
/dev/sr0 10G 10G 0 100% /run/media/oracle/OL-8-5-0-BaseOS-x86_64

[root@oracle-21 ~]#mount /dev/sdb1 /oradata
[root@oracle-21 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 3.9G 0 3.9G 0% /dev
tmpfs 3.9G 0 3.9G 0% /dev/shm
tmpfs 3.9G 0 3.9G 0% /sys/fs/cgroup
/dev/mapper/ol-root 26G 5.4G 21G 21% /
/dev/sda1 1014M 318M 697M 32% /boot
tmpfs 796M 28K 796M 1% /run/user/1000
/dev/sr0 10G 10G 0 100% /run/media/oracle/OL-8-5-0-BaseOS-x86_64
/dev/sdb1 25G 45M 24G 1%/oradata
[root@oracle-21 ~]#

The configuration of this partition will disappear on the next reboot, requiring you to manually remount each and every mount point that you need to access at the SSOO level. During this time, you will obviously be unable to access the data stored in that directory. To prevent this from happening, you need to configure the fstab file, located in the /etc path. The /etc/fstab file contains the configuration that tells the system how to mount the computer's drives. It is a file with six columns to configure.

As we have indicated before with the mkfs command, the parameters of the mount point vary according to needs, in our case, these parameters are enough.

/dev/sdb1 /oradata ext4 defaults 0 0

As a last step, the only thing left to do is to assemble it.

mount /oradata

Let's repeat the following steps with the devices (sdc, sdd) in order to have /oradata /oradata1 /oradata2

The final picture would be something like the following:

With this storage configuration in place, you can now proceed with creating the database; the data must be distributed across the newly created directories. With the advent of ASM, this configuration has become practically obsolete for larger installations. For Oracle Automatic Storage Manager (ASM) to identify the disks, they must be consistently identified with specific properties and permissions. This can be done (on Linux) using ASMLib or Udev; in this example, we will add the disks using the Linux device manager, UDEV. In a future post, we will describe how to configure the necessary settings so that the disks are managed via UDEV or ASMLib.