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disk operation

|-----------------------disk---------------------|
|-----partition------|---------partition---------|
|-----filesystem-----|---------filesystem--------|

ref: https://stackoverflow.com/questions/24429949/device-vs-partition-vs-file-system-vs-volume-how-do-these-concepts-relate-to-ea

Partition Table Type

A data structure that provides basic information for the OS about the partition of the hard disk.

  • MBR: Master Boot Record.

    Used with the legacy BIOS firmware.

    An older standard. (only support < 2T disk)

  • GPT: GUID Partition Table

    Used with the EFI firmware. (not compatible with BIOS)

    Current default.

    GPT contains a fake MBR at the beginning of its space. This MBR shows the drive as being a single MBR partition to cope with tools which do not recognize GPT.

Filesystem

A way of storing data inside the partitions.

  • EXT / EXT2 / EXT3

    older version of EXT.

  • EXT4

    current default for Linux, Android.

    support both Windows and Linux. support < 1EB = 2^20 TB.

  • FAT

    much older, for Windows. FAT16 < 4GB, FAT32 < 32 GB.

  • NTFS

    current default for Windows.

  • exFAT

    support both Windows and Linux, usually for swap and recovery.

check disk state and mount point

  • fdisk: check all physically loaded disks

    $ sudo fdisk -l
Disk /dev/sda: 1.8 TiB, 2000398934016 bytes, 3907029168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 943FD3C6-B398-4D2E-8A66-58991158B3A2

Device          Start        End    Sectors  Size Type
/dev/sda1        2048    1050623    1048576  512M EFI System
/dev/sda2     1050624 3905028095 3903977472  1.8T Linux filesystem
/dev/sda3  3905028096 3907028991    2000896  977M Linux swap


Disk /dev/sdb: 953.9 GiB, 1024209543168 bytes, 2000409264 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 /dev/sdc: 931.5 GiB, 1000204886016 bytes, 1953525168 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 /dev/sdd: 931.5 GiB, 1000204886016 bytes, 1953525168 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

    Linux Filesystem is where the root / is mounted.

    EFI System (Extensible Firmware Interface) is used to boot the system. (UEFI firmware loads the files on the EFI System)

  • mount check the mount 

    $ mount
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)
udev on /dev type devtmpfs (rw,nosuid,relatime,size=131978096k,nr_inodes=32994524,mode=755)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
tmpfs on /run type tmpfs (rw,nosuid,noexec,relatime,size=26402968k,mode=755)
/dev/sda2 on / type ext4 (rw,relatime,errors=remount-ro,data=ordered)
securityfs on /sys/kernel/security type securityfs (rw,nosuid,nodev,noexec,relatime)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
tmpfs on /run/lock type tmpfs (rw,nosuid,nodev,noexec,relatime,size=5120k)
tmpfs on /sys/fs/cgroup type tmpfs (ro,nosuid,nodev,noexec,mode=755)
cgroup on /sys/fs/cgroup/systemd type cgroup (rw,nosuid,nodev,noexec,relatime,xattr,release_agent=/lib/systemd/systemd-cgroups-agent,name=systemd)
pstore on /sys/fs/pstore type pstore (rw,nosuid,nodev,noexec,relatime)
efivarfs on /sys/firmware/efi/efivars type efivarfs (rw,nosuid,nodev,noexec,relatime)
cgroup on /sys/fs/cgroup/freezer type cgroup (rw,nosuid,nodev,noexec,relatime,freezer)
cgroup on /sys/fs/cgroup/rdma type cgroup (rw,nosuid,nodev,noexec,relatime,rdma)
cgroup on /sys/fs/cgroup/devices type cgroup (rw,nosuid,nodev,noexec,relatime,devices)
cgroup on /sys/fs/cgroup/cpu,cpuacct type cgroup (rw,nosuid,nodev,noexec,relatime,cpu,cpuacct)
cgroup on /sys/fs/cgroup/blkio type cgroup (rw,nosuid,nodev,noexec,relatime,blkio)
cgroup on /sys/fs/cgroup/net_cls,net_prio type cgroup (rw,nosuid,nodev,noexec,relatime,net_cls,net_prio)
cgroup on /sys/fs/cgroup/hugetlb type cgroup (rw,nosuid,nodev,noexec,relatime,hugetlb)
cgroup on /sys/fs/cgroup/cpuset type cgroup (rw,nosuid,nodev,noexec,relatime,cpuset)
cgroup on /sys/fs/cgroup/perf_event type cgroup (rw,nosuid,nodev,noexec,relatime,perf_event)
cgroup on /sys/fs/cgroup/memory type cgroup (rw,nosuid,nodev,noexec,relatime,memory)
cgroup on /sys/fs/cgroup/pids type cgroup (rw,nosuid,nodev,noexec,relatime,pids)
systemd-1 on /proc/sys/fs/binfmt_misc type autofs (rw,relatime,fd=35,pgrp=1,timeout=0,minproto=5,maxproto=5,direct,pipe_ino=55306)
debugfs on /sys/kernel/debug type debugfs (rw,relatime)
mqueue on /dev/mqueue type mqueue (rw,relatime)
hugetlbfs on /dev/hugepages type hugetlbfs (rw,relatime,pagesize=2M)
fusectl on /sys/fs/fuse/connections type fusectl (rw,relatime)
configfs on /sys/kernel/config type configfs (rw,relatime)
/dev/sdb on /data2 type ext4 (rw,relatime,data=ordered)
/dev/sdc on /data3 type ext4 (rw,relatime,data=ordered)
/dev/sdd on /data4 type ext4 (rw,relatime,data=ordered)
/dev/sda1 on /boot/efi type vfat (rw,relatime,fmask=0077,dmask=0077,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro)
tmpfs on /run/user/1002 type tmpfs (rw,nosuid,nodev,relatime,size=26402968k,mode=700,uid=1002,gid=1002)

    Note the physical disk lines:

    /dev/sda2 on / type ext4 (rw,relatime,errors=remount-ro,data=ordered)
/dev/sdb on /data2 type ext4 (rw,relatime,data=ordered)
/dev/sdc on /data3 type ext4 (rw,relatime,data=ordered)
/dev/sdd on /data4 type ext4 (rw,relatime,data=ordered)
/dev/sda1 on /boot/efi type vfat

  • df only shows mounted fs and path.

    $ df -h
Filesystem      Size  Used Avail Use% Mounted on
udev            126G     0  126G   0% /dev
tmpfs            26G   19M   26G   1% /run
/dev/sda2       1.8T  1.5T  214G  88% /
tmpfs           126G     0  126G   0% /dev/shm
tmpfs           5.0M  4.0K  5.0M   1% /run/lock
tmpfs           126G     0  126G   0% /sys/fs/cgroup
/dev/sdb        939G  562G  330G  64% /data2
/dev/sdc        917G  729G  142G  84% /data3
/dev/sdd        917G   72M  871G   1% /data4
/dev/sda1       511M  3.7M  508M   1% /boot/efi
tmpfs            26G     0   26G   0% /run/user/1002

  • lsblk the most clear and useful one.

    $ sudo lsblk
NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sdd      8:48   0 931.5G  0 disk /data4
sdb      8:16   0 953.9G  0 disk /data2
sdc      8:32   0 931.5G  0 disk /data3
sda      8:0    0   1.8T  0 disk
├─sda2   8:2    0   1.8T  0 part /
├─sda3   8:3    0   977M  0 part [SWAP]
└─sda1   8:1    0   512M  0 part /boot/efi

    To check if the disk is SSD or HDD (ROTAtional):

    $ lsblk -d -o name,rota
NAME ROTA
sda     0
sdb     0
sdc     1

    where ROTA == 1 means HDD, and ROTA == 0 means SSD.

Add a new disk

  • Plug in the hardware

  • Check is it detected

    sudo fdisk -l 
# should see /dev/sdb, /dev/sdc, ...

  • (Optional) make partitions

    sudo fdisk /dev/sdb
# >>> p
# >>> n
# ...

  • make filesystem

    sudo mkfs -t ext4 /dev/sdb 
# sudo mkfs -t ext4 /dev/sdb1 # if partitioned

# exfat is supported by both Windows and Linux, you can use it too:
sudo apt install exfatprogs
sudo mkfs.exfat /dev/sdb

  • mount

    sudo mkdir /data2
sudo mount /dev/sdb /data2

  • set auto-mount after reboot

    sudo vim /etc/fstab
# add a line: 

# <disk> <mount> <filesystem> <option> <dump, should be 0> <pass, root disk shoule be 1, other disk should be 2>

/dev/sdb /data2 ext4 defaults 0 2

  • check auto-mount

    sudo mount -av