Linux System Management-(1)-Disk Management

Linux Disk Management



Block devices: block, Access unit "blocks", disk
Character device: Char, Access unit "character", keyboard
Device files: Associated to a device driver that can communicate with the corresponding hardware device;

Device Number:
Main device number: Major numbers, identifying device types

Second device number: Minor numbers, identifying different devices under the same type

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HDD Interface type:
Parallel:
ide:133mb/s
scsi:640mb/s
Serial:
sata:6gbps
sas:6gbps
usb:480mb/s

/dev/dev_file
Device file name for disk device:

IDE:/DEV/HD
SCSI, SATA, SAS, USB:/DEV/SD
Different devices: A-Z
/DEV/SDA,/dev/sdb, ...
Different partitions on the same device: 1, 2, ...
/DEV/SDA1,/dev/sda5

Mechanical HDD:

Slice:cylinder/

Tracks: Track

Sector:Sector
Cylindrical Surface : Parallel disks, tracks in the same position form cylinders

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                  How to partition:
                     by cylinder

                 0 Track 0 sector:512bytes  (typically used for booting)
                     mbr:master Boot Record
           & nbsp;            446bytes:boot loader
                         64bytes: Partition table
                              16bytes: Identifies a partition

2BYTES:55AA for testing

# #Flash的存储位, can only change from 1 to 0, so after wiping, the unit is 1, at this time can write directly, when written 0, and then write 1 is not, must erase, erase and become 1.
Each byte is written in 55, then a AA, so that each bit is written and wiped again, indicating that the location of this byte is easy to use

4 primary partitions;
3 primary partition +1 extension (n logical partitions)

Logical Partitioning

Partition management tool: Fdisk
Fdisk: For a hard disk, you can manage up to 15 partitions;

# fdisk-l [-u] [device ...]

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# fdisk Device

Subcommands: Administrative functions
P:print, showing existing partitions;

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n:new, creating

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d:delete, deleting

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W:write, write to disk and exit
Q:quit, discard the update and exit
M: Get Help
L: The partition ID of the list

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T: adjust the partition ID
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Notifies the kernel to re-read the hard disk partition table:
Partx-a/dev/device
-N m:n

Linux file System management:
    linux File system: ext2, Ext3, Ext4, XFS, Btrfs, ReiserFS, JFS, swap
       &N Bsp;swap: Swap partition
         disc: iso9660
    windows:fat32, NTFS
    unix:ffs, UFS, JFS2
     Network File system: NFS, CIFS
     Clustered file system: GFS2, OCFS2
     Distributed File system: Ceph,
        moosefs, MogileFS, GlusterFS, Lustre

     Depending on whether it supports the "journal" feature:
         journaled file system: ext3, Ext4, Xfs...
         Non-journaled file systems: ext2, VFAT

     File system components:
         Modules in the kernel: Ext4, XFS, VFAT
         User space management tools: MKFS.EXT4, MKFS.XFS, Mkfs.vfat

    linux Virtual file system: VFS

To create a file system:
MKFS command:
(1) # MKFS. Fs_type/dev/device
Ext4
Xfs
Btrfs
Vfat
(2) # mkfs-t Fs_type/dev/device

-L ' LABEL ': Set volume label

Mke2fs:ext Series file system dedicated management tools
-T {EXT2|EXT3|EXT4}
-B {1024|2048|4096}
-L ' LABEL '
-j: Equivalent to-t ext3
MKFS.EXT3 = mkfs-t ext3 = mke2fs-j = Mke2fs-t ext3
-I #: Create an inode for each number of bytes in the data space, which should not be less than the size of the block;
-N #: How many inode to create for the data space;
-M #: Percentage of space reserved for managers;
-O feature[,...] : Enable the specified attribute
-O ^feature: Turn off specified attributes

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Mkswap: Creating Swap partitions
Mkswap [Options] Device
-L ' LABEL '

Premise: adjust its partition ID to 82;

Other common tools:

Blkid: Block Device properties Information View
Blkid [OPTION] ... [DEVICE]
-U UUID: Find the corresponding device based on the specified UUID
-L Label: finds the corresponding device according to the specified label

E2label: Manage label for ext series File system
# E2label DEVICE [LABEL]

TUNE2FS: Reset the values of the EXT series file system adjustable parameters
-L: View the specified file system super block information; Super Block
-L ' LABEL ': Modify volume label
-M #: Fixed percentage of space reserved for administrators
-j: Upgrade ext2 to Ext3
-O: File System Properties enabled or disabled
-O: Adjust default mount options for the file system
-U uuid: Modify the UUID number;

DUMPE2FS:
-H: View Super block information

File System Detection：
Fsck:file System CheCk
Fsck. Fs_type
Fsck-t Fs_type
-A: Auto fix error
-r: Interactive fix error

Note:fs_type must be the same as the file type on the partition;

E2fsck:ext series file-specific detection and repair tool
-Y: Auto answer yes;
-F: Forced repair;

Linux System Management-(1)-Disk Management