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11-07-2020 |
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Disk
Management |
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Hard Disk (Hard Drive) IDE Linux will handle these kind fo devices
/dev/hda SCSI Linux will handle these kind of devices
/dev/sda Virtual drive Linux will handle these kind of
devices /dev/vda |
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SCSI Small Computer System Interface is a set of
standards for physically connecting and transferring data between computers
and peripheral devices. The SCSI standards define commands, protocols, electrical,
optical and logical interfaces |
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List the
disk |
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Lsblk [root@zmpt01 ~]# lsblk NAME
MAJ:MIN RM SIZE RO TYPE
MOUNTPOINT sda
8:0 0 16G
0 disk ├─sda1
8:1 0 1G
0 part /boot └─sda2 8:2 0
15G 0 part ├─centos-root 253:0
0 13.4G 0 lvm /
└─centos-swap 253:1
0 1.6G 0 lvm
[SWAP] sdb 8:16
0 16G 0 disk sdc
8:32 0 8G
0 disk sr0
11:0 1 1024M 0 rom |
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Linux handles the devices as files |
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[root@zmpt01 ~]# ls -l /dev/sd* brw-rw----. 1 root disk 8, 0 Nov
7 16:54 /dev/sda brw-rw----. 1 root disk 8, 1 Nov
7 16:54 /dev/sda1 brw-rw----. 1 root disk 8, 2 Nov
7 16:54 /dev/sda2 brw-rw----. 1 root disk 8, 16 Nov 7 16:54 /dev/sdb < ---Working on this disk brw-rw----. 1 root disk 8, 32 Nov 7 16:54 /dev/sdc |
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Three comman ways to manage the disk -
Fdisk Fixed
disk setup program -
Gdisk Same as
fdisk, but uses GPT -
LVM Logical
Volume Manager |
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FDISK |
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Fixed Disk Setup Program /dev/sdb 16GB
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[root@zmpt01 ~]# fdisk /dev/sdb Command (m for help): m Command (m for help): n Select (default p): p Partition number (1-4, default 1): 1 First sector (2048-33554431, default 2048): < ---hit enter Last sector, +sectors or +size{K,M,G}
(2048-33554431, default 33554431): +8G Command (m for help): w The partition table has been altered! |
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10-08-2020 |
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Run partprobe [root@zmpt01 ~]# partprobe |
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[root@zmpt01 ~]# lsblk NAME
MAJ:MIN RM SIZE RO TYPE
MOUNTPOINT sda
8:0 0 16G
0 disk ├─sda1
8:1 0 1G
0 part /boot └─sda2 8:2 0
15G 0 part ├─centos-root 253:0
0 13.4G 0 lvm /
└─centos-swap 253:1
0 1.6G 0 lvm
[SWAP] sdb
8:16 0 16G
0 disk └─sdb1
8:17 0 8G
0 part < ---New created partition sdc
8:32 0 8G
0 disk sr0
11:0 1 1024M 0 rom |
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Creating the file system |
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In computing, a file system or filesystem controls
how data is stored(writing) and retrieved(access) |
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[root@zmpt01 ~]# mkfs.ext4 /dev/sdb1 < ---Command to create EXT4
file system mke2fs 1.42.9 (28-Dec-2013) Filesystem label= OS type: Linux Block
size=4096 (log=2) < ---4KB is the default
black space (smallest useable block) Fragment size=4096 (log=2) Stride=0 blocks, Stripe width=0 blocks 524288 inodes, 2097152 blocks 104857 blocks (5.00%) reserved for the super user First data block=0 Maximum filesystem blocks=2147483648 64 block groups 32768 blocks per group, 32768 fragments per group 8192 inodes per group Superblock backups stored on blocks: 32768,
98304, 163840, 229376, 294912, 819200, 884736, 1605632 Allocating group tables: done Writing inode tables: done Creating journal (32768 blocks): done Writing superblocks and filesystem accounting
information: done |
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Binary is base 2 = 1 0 1 = on 0 = off 2^8
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File System structure |
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Mount the file system makign it available for
useage |
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[root@zmpt01 ~]# mkdir /DATA [root@zmpt01 ~]# mount /dev/sdb1 /DATA/ < ---you have to provide absolute path
when mounting
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To see the disk and mount point being used |
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[root@zmpt01 ~]# df -h Filesystem Size Used Avail Use% Mounted on devtmpfs 484M 0
484M 0% /dev tmpfs 496M 0
496M 0% /dev/shm tmpfs 496M 6.8M
489M 2% /run tmpfs 496M 0
496M 0% /sys/fs/cgroup /dev/mapper/centos-root 14G
1.8G 12G 14% / /dev/sda1 1014M 136M
879M 14% /boot tmpfs 100M 0
100M 0% /run/user/0 /dev/sdb1 7.8G 36M
7.3G 1% /DATA |
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[root@zmpt01 ~]# lsblk NAME
MAJ:MIN RM SIZE RO TYPE
MOUNTPOINT sda
8:0 0 16G
0 disk ├─sda1
8:1 0 1G
0 part /boot └─sda2 8:2 0
15G 0 part ├─centos-root 253:0
0 13.4G 0 lvm /
└─centos-swap 253:1
0 1.6G 0 lvm
[SWAP] sdb
8:16 0 16G
0 disk └─sdb1 8:17 0
8G 0 part /DATA sdc
8:32 0 8G
0 disk sr0
11:0 1 1024M 0 rom |
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Unmount the disk |
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[root@zmpt01 ~]# umount /DATA/ NAME
MAJ:MIN RM SIZE RO TYPE
MOUNTPOINT sda
8:0 0 16G
0 disk ├─sda1
8:1 0 1G
0 part /boot └─sda2 8:2 0
15G 0 part ├─centos-root 253:0 0 13.4G
0 lvm /
└─centos-swap 253:1
0 1.6G 0 lvm
[SWAP] sdb
8:16 0 16G
0 disk └─sdb1 8:17 0
8G 0 part sdc
8:32 0 8G
0 disk sr0
11:0 1 1024M 0 rom |
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Reboot |
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[root@zmpt01 ~]# df h The file system is not mounted |
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FSTAB File System Table |
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Configuration file helpful during boot for mounting
disks /etc/fstab [root@zmpt01 ~]# vi /etc/fstab Copy th existing line and paset into new line and
edit as needed
[root@zmpt01 ~]# mount a < ---this command will read /etc/fstab and mounts
the files if not already mounted The file system will be mounted during boot up ***persistence with the reboot*** |
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Changing the mount point |
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[root@zmpt01 DATA]# touch file{1..100} /dev/sdb1 7.8G 36M
7.3G 1% /DATA < ---Files are actually written to /dev/sdb1 [root@zmpt01 ~]# umount /DATA [root@zmpt01 ~]# df h [root@zmpt01 ~]# cd /DATA/ [root@zmpt01 DATA]# ls [root@zmpt01 ~]# mount /dev/sdb1 /IBM [root@zmpt01 ~]# df -h Filesystem Size Used Avail Use% Mounted on devtmpfs 484M 0
484M 0% /dev tmpfs 496M 0
496M 0% /dev/shm tmpfs 496M 6.8M
489M 2% /run tmpfs 496M 0
496M 0% /sys/fs/cgroup /dev/mapper/centos-root 14G
1.8G 12G 14% / /dev/sda1 1014M 136M
879M 14% /boot tmpfs 100M 0
100M 0% /run/user/0 /dev/sdb1 7.8G 36M
7.3G 1% /IBM <
---mount point is changed to IBM, but data will still be available [root@zmpt01 IBM]# ls file1
file2 file30 file41
file52 file63 file74
file85 file96 |
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UUID Universal Unique
Identifier |
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[root@zmpt01 ~]# blkid /dev/sdb1: UUID="1dfbb3a5-8b04-4883-89e7-ceb9e78db6e4"
TYPE="ext4" [root@zmpt01 ~]# vi /etc/fstab #/dev/sdb1 /DATA ext4 defaults 0 0 UUID=1dfbb3a5-8b04-4883-89e7-ceb9e78db6e4 /DATA ext4 defaults 0 0 [root@zmpt01 ~]# mount a [root@zmpt01 ~]# df h /dev/sdb1 7.8G 36M
7.3G 1% /DATA <
---UUID is associated with /dev/sdb1 |
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Mount using label |
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[root@zmpt01 ~]# e2label /dev/sdb1 zmpt01 [root@zmpt01 ~]# blkid /dev/sda1:
UUID="160e6caa-b0a9-468b-9de1-04189acc84ce" TYPE="xfs" /dev/sda2:
UUID="oLnQZF-bJU0-02T3-t0wF-DhnB-2JI6-CQI9f2"
TYPE="LVM2_member" /dev/sdb1: LABEL="zmpt01"
UUID="1dfbb3a5-8b04-4883-89e7-ceb9e78db6e4" TYPE="ext4" /dev/mapper/centos-root:
UUID="5c79b16a-cfd4-4d5a-8e9c-b9b1a37b4936" TYPE="xfs" /dev/mapper/centos-swap:
UUID="c7801c38-9828-49b2-8a12-7610376d8b8a" TYPE="swap" [root@zmpt01 ~]# vi /etc/fstab LABEL="zmpt01" /DATA ext4 defaults 0 0 < ---using the LABEL [root@zmpt01 ~]# mount -a [root@zmpt01 ~]# df h /dev/sdb1 7.8G 36M
7.3G 1% /DATA < ---Mounted using LABEL |
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Multiple filesystem on same
disk |
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/dev/sdb 16GB
[root@zmpt01 ~]# fdisk /dev/sdb Command (m for help): m Command (m for help): p Command (m for help): n Select (default p): p Partition number (2-4, default 2): 2 First sector (16779264-33554431, default
16779264): < ---hit Enter use default value Last sector, +sectors or +size{K,M,G}
(16779264-33554431, default 33554431): +2G Command (m for help): p Disk /dev/sdb: 17.2 GB, 17179869184 bytes, 33554432
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: 0x5460be06 Device
Boot Start End Blocks
Id System /dev/sdb1
2048 16779263 8388608
83 Linux /dev/sdb2
16779264 20973567 2097152
83 Linux < ---New partition is created Command (m for help): w |
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[root@zmpt01 ~]# lsblk NAME
MAJ:MIN RM SIZE RO TYPE
MOUNTPOINT sda
8:0 0 16G
0 disk ├─sda1
8:1 0 1G
0 part /boot └─sda2 8:2 0
15G 0 part ├─centos-root 253:0
0 13.4G 0 lvm /
└─centos-swap 253:1
0 1.6G 0 lvm
[SWAP] sdb
8:16 0 16G
0 disk ├─sdb1
8:17 0 8G
0 part /DATA └─sdb2 8:18 0
2G 0 part < ---Newly created
partition 2GB sdc
8:32 0 8G
0 disk |
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[root@zmpt01 ~]# mkfs.xfs /dev/sdb2 |
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[root@zmpt01 ~]# mount /dev/sdb2 /IBM/ |
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[root@zmpt01 ~]# df -h Filesystem Size Used Avail Use% Mounted on devtmpfs 484M 0
484M 0% /dev tmpfs
496M 0
496M 0% /dev/shm tmpfs 496M 6.8M
489M 2% /run tmpfs 496M 0
496M 0% /sys/fs/cgroup /dev/mapper/centos-root 14G
1.8G 12G 14% / /dev/sda1 1014M 136M
879M 14% /boot tmpfs 100M 0
100M 0% /run/user/0 /dev/sdb1 7.8G 36M
7.3G 1% /DATA /dev/sdb2 2.0G 33M
2.0G 2% /IBM < ---disk is mounted to /IBM |
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Make appropriate entry into /etc/fstab /dev/sdb2 /IBM xfs defaults 0 0 |
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[root@zmpt01 ~]# mount a [root@zmpt01 ~]# df -h Filesystem Size Used Avail Use% Mounted on devtmpfs 484M 0
484M 0% /dev tmpfs 496M 0
496M 0% /dev/shm tmpfs 496M 6.8M
489M 2% /run tmpfs 496M 0
496M 0% /sys/fs/cgroup /dev/mapper/centos-root 14G
1.8G 12G 14% / /dev/sda1 1014M 136M
879M 14% /boot tmpfs
100M 0
100M 0% /run/user/0 /dev/sdb1 7.8G 36M
7.3G 1% /DATA /dev/sdb2 2.0G 33M
2.0G 2% /IBM < ---disk is mounted to /IBM
using mount -a |
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|
11-14-2020 |
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Extending inodes |
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|
To create random amount of blank files |
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|
touch file{1..110000} |
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[root@zmpt01 IBM]# df h /dev/sdb2 2.0G 582M
1.5G 29% /IBM |
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|
[root@zmpt01 IBM]# df I < ---this is used for checking the
iNodes /dev/sdb2 1048640 1048640 0
100% /IBM |
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Ext4 file system [root@zmpt01 ~]# df -i /dev/sdb1 Filesystem
Inodes IUsed IFree IUse%
Mounted on /dev/sdb1 524288
110 524178 1% /DATA [root@zmpt01 ~]# umount /dev/sdb1 [root@zmpt01 ~]# mkfs.ext4 -N 1000000 /dev/sdb1 < ---ALL DATA will be deleted [root@zmpt01 ~]# mount /dev/sdb1 /DATA/ [root@zmpt01 ~]# df -i /dev/sdb1 1000448 11 1000437 1% /DATA |
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|
Increase the partition size |
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|
[root@zmpt01 ~]# df h /dev/sdb2 2.0G 582M
1.5G 29% /IBM < --- Increase size of file system to
4GB |
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Unmount the partition that needs to be extended [root@zmpt01 ~]# umount /IBM/ [root@zmpt01 ~]# fdisk /dev/sdb Command (m for help): m Command (m for help): d Command (m for help): w [root@zmpt01 ~]# fdisk /dev/sdb Command (m for help): p Command (m for help): n Partition type: p primary (1 primary, 0 extended, 3 free) e extended Select (default p): p Partition number (2-4, default 2): 2 First sector (16779264-33554431, default 16779264): Using default value 16779264 Last sector, +sectors or +size{K,M,G}
(16779264-33554431, default 33554431): +4G Partition 2 of type Linux and of size 4 GiB is set Command (m for help): p Device
Boot Start End Blocks
Id System /dev/sdb1
2048 16779263 8388608
83 Linux /dev/sdb2
16779264 25167871 4194304
83 Linux Command (m for help): w [root@zmpt01 ~]# partprobe [root@zmpt01 ~]# mount a [root@zmpt01 ~]# df h /dev/sdb2 2.0G
582M 1.5G 29% /IBM [root@zmpt01 ~]# xfs_growfs /dev/sdb2 [root@zmpt01 IBM]# df h /dev/sdb2 4.0G
582M 3.5G 15% /IBM |
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|
Patititon Inforamtion |
|||||||||||||||||||
|
-
You can have
maximum of four primary partitions on single disk -
If you want to
create more than four partitions -
Then you need
to create extended partion, then you can nest multiple partitions inside extended
partition |
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|
|
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|
SWAP |
|||||||||||||||||||
|
Swap is a space on a disk that is used when the amount
of physical memory (RAM ) is full. When a lunux system runs out of RAM,
inactive pages are moved from RAM to swap
space. Swap space can take the
form of either a dedicated swap
partition or a swap file. -
What is swap?
Swap is standby memory -
Its a virtual
memory used from hard drive -
Real memory is
1GB -
SWAP memory is
1.6 GB -
Total useable
size is 2.6 GB -
If the real
memory is full the swap is utilized -
OS will mvoe
inactive processes to the swap memory -
Think of it as
a safety net for Physical Memory. |
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|
[root@zmpt01 ~]# fdisk /dev/sdb Command (m for help): p Device
Boot Start End Blocks
Id System /dev/sdb1
2048 16779263 8388608
83 Linux /dev/sdb2
16779264 25167871
4194304 83 Linux Command (m for help): m Command (m for help): n Partition type: p primary (2 primary, 0 extended, 2 free) e extended Select (default p): p Partition number (3,4, default 3): 3 First sector (25167872-33554431, default 25167872): Using default value 25167872 Last sector, +sectors or +size{K,M,G}
(25167872-33554431, default 33554431): +2G Partition 3 of type Linux and of size 2 GiB is set Command (m for help): m Command (m for help): t Partition number (1-3, default 3): 3 Hex code (type L to list all codes): 82 Changed type of partition 'Linux' to 'Linux swap /
Solaris' Command (m for help): p Disk /dev/sdb: 17.2 GB, 17179869184 bytes, 33554432
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: 0x5460be06 Device
Boot Start End Blocks
Id System /dev/sdb1
2048 16779263 8388608
83 Linux /dev/sdb2
16779264 25167871 4194304
83 Linux /dev/sdb3
25167872 29362175 2097152
82 Linux swap / Solaris Command (m for help): w [root@zmpt01 ~]# partprobe [root@zmpt01 ~]# mkswap /dev/sdb3 < ---creates the swap partition [root@zmpt01 ~]# swapon /dev/sdb3 < ----make the swap useable [root@zmpt01 ~]# vi /etc/fstab /dev/sdb3 swap swap defaults 0 0 [root@zmpt01 ~]# free -h
total used free shared
buff/cache available Mem:
991M 284M 345M 1.6M 360M 549M Swap:
3.6G 279M 3.3G |
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|
[root@zmpt01 ~]# swapoff /dev/sdb3 [root@zmpt01 ~]# free -h
total used free shared
buff/cache available Mem:
991M 283M 347M 1.6M 360M 550M Swap:
1.6G 278M 1.3G [root@zmpt01 ~]# free -h
total used
free shared buff/cache
available Mem:
991M 283M 347M 1.6M 360M 550M Swap:
1.6G 278M 1.3G [root@zmpt01 ~]# vi /etc/fstab [root@zmpt01 ~]# swapon a [root@zmpt01 ~]# free -h
total used free shared
buff/cache available Mem:
991M 284M 345M 1.6M 360M 549M Swap:
3.6G 278M 3.3G |
