Linux磁盘管理及文件系统使用

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• Linux中磁盘命名：
  IDE类型：/dev/hd[a-z]
  SCSI类型：/dev/sd[a-z]

• 一块磁盘经过哪些步骤才能够使用：分区（非必需）-->格式化-->挂载；磁盘分区的类型有MBR（master boot record）和GPT（GUID Partition Table），主要区别在MBR只能分4个主分区超过需要分为逻辑分区，磁盘容量最大不超过2T，超过部分无法识别。

• MBR 也就是主引导记录，位于硬盘的 0 磁道、0 柱面、1 扇区中，主要记录了启动引导程序和磁盘的分区表：
  
  由于分区表大小固定：最多只能分4个，超过需要使用扩展分区来划分逻辑分区，即使主分区再分配一个，逻辑分区命名从/dev/sda5开始。
• 分区

• fdisk：不适用于GPT分区。
  1.查看磁盘分区信息：
  用法:fdisk -l [-u] [device...]：列出指定磁盘设备上的分区情况；

  [root@xt ~]# fdisk -l
  Disk /dev/sda: 21.5 GB, 21474836480 bytes, 41943040 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: 0x00036ca6
  Device Boot      Start         End      Blocks   Id  System
  /dev/sda1            2048    20973567    10485760   83  Linux
  /dev/sda2        20973568    25167871     2097152   82  Linux swap / Solaris
  /dev/sda3        25167872    25692159      262144   83  Linux

  2.分区管理，fdisk提供了交互接口来管理分区
  用法：fdisk [options] <disk>

  [root@xt ~]# fdisk /dev/sda 
  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.
  Command (m for help): m
  Command action
  a   toggle a bootable flag
  b   edit bsd disklabel
  c   toggle the dos compatibility flag
  d   delete a partition：删除分区
  g   create a new empty GPT partition table
  G   create an IRIX (SGI) partition table
  l   list known partition types
  m   print this menu
  n   add a new partition：创建新分区
  o   create a new empty DOS partition table
  p   print the partition table：列出现有分区
  q   quit without saving changes ：不保存退出
  s   create a new empty Sun disklabel
  t   change a partition‘s system id：修改分区类型
  u   change display/entry units
  v   verify the partition table
  w   write table to disk and exit：保存退出
  x   extra functionality (experts only)

  3.在已经分区并且已经挂载其中某个分区的磁盘设备上创建的新分区，内核可能无法直接识别，通知内核重读分区表
  查看：cat /proc/partitions
  CentOS 5：partprobe [device]
  CentOS 6,7：partx, kpartx
  partx -a [device]
  kpartx -af [device]

• parted 、gdisk能够使用GPT模式
  1.查看磁盘信息
  parted [options] [device]

  [root@xt ~]# parted -l 
  Model: VMware, VMware Virtual S (scsi)
  Disk /dev/sda: 21.5GB
  Sector size (logical/physical): 512B/512B
  Partition Table: msdos
  Disk Flags: 
  Number  Start   End     Size    Type     File system     Flags
  1      1049kB  10.7GB  10.7GB  primary  xfs
  2      10.7GB  12.9GB  2147MB  primary  linux-swap(v1)
  3      12.9GB  13.2GB  268MB   primary  btrfs
  Error: /dev/sdb: unrecognised disk label
  Model: VMware, VMware Virtual S (scsi)                                    
  Disk /dev/sdb: 3221GB
  Sector size (logical/physical): 512B/512B
  Partition Table: unknown
  Disk Flags: 

  2.分区管理
  用法： parted device

  [root@xt ~]# parted /dev/sdb
  GNU Parted 3.1
  Using /dev/sdb
  Welcome to GNU Parted! Type ‘help‘ to view a list of commands.
  (parted) help         #查看帮助                                                    
  align-check TYPE N                        check partition N for TYPE(min|opt) alignment
  help [COMMAND]                           print general help, or help on COMMAND
  mklabel,mktable LABEL-TYPE               create a new disklabel (partition table)
  mkpart PART-TYPE [FS-TYPE] START END     make a partition
  name NUMBER NAME                         name partition NUMBER as NAME
  print [devices|free|list,all|NUMBER]     display the partition table, available devices, free space, all found
      partitions, or a particular partition
  quit                                     exit program
  rescue START END                         rescue a lost partition near START and END
  rm NUMBER                                delete partition NUMBER
  select DEVICE                            choose the device to edit
  disk_set FLAG STATE                      change the FLAG on selected device
  disk_toggle [FLAG]                       toggle the state of FLAG on selected device
  set NUMBER FLAG STATE                    change the FLAG on partition NUMBER
  toggle [NUMBER [FLAG]]                   toggle the state of FLAG on partition NUMBER
  unit UNIT                                set the default unit to UNIT
  version                                  display the version number and copyright information of GNU Parted
  (parted) print                                                            
  Error: /dev/sdb: unrecognised disk label
  Model: VMware, VMware Virtual S (scsi)                                    
  Disk /dev/sdb: 3221GB
  Sector size (logical/physical): 512B/512B
  Partition Table: unknown
  Disk Flags: 
  (parted) mklabel gpt  #修改磁盘结构类型："aix", "amiga", "bsd", "dvh", "gpt", "loop", "mac", "msdos", "pc98", or "sun"
  Warning: The existing disk label on /dev/sdb will be destroyed and all data on this disk will be lost. Do you want
  to continue?
  Yes/No? yes                                                               
  (parted) mkpart    #交互式分区
  Partition name?  []? primary #分区名称： primary", "logical", or "extended"                            File system type?  [ext2]? ext4   #文件系统类型                                        
  Start? 0
  End? 1000    #分配分区大小                                                             
  Warning: The resulting partition is not properly aligned for best performance.
  Ignore/Cancel? Ignore                                                     
  (parted) print                                                            
  Model: VMware, VMware Virtual S (scsi)
  Disk /dev/sdb: 3221GB
  Sector size (logical/physical): 512B/512B
  Partition Table: gpt
  Disk Flags: 
  Number  Start   End     Size    File system  Name     Flags
  1      17.4kB  1000MB  1000MB               primary
  (parted) rm 1    #删除分区1                                                         
  (parted) p                                                                
  Model: VMware, VMware Virtual S (scsi)
  Disk /dev/sdb: 3221GB
  Sector size (logical/physical): 512B/512B
  Partition Table: gpt
  Disk Flags: 
  Number  Start  End  Size  File system  Name  Flags
  ==============================================================
  (parted) mkpart primary 0 2000G    # 方法2分区 mkpart part-type [fs-type] start end
  Warning: The resulting partition is not properly aligned for best performance.
  Ignore/Cancel? i                                                          
  (parted) p                                                                
  Model: VMware, VMware Virtual S (scsi)
  Disk /dev/sdb: 3221GB
  Sector size (logical/physical): 512B/512B
  Partition Table: gpt
  Disk Flags: 
  Number  Start   End     Size    File system  Name     Flags
  1      17.4kB  2000GB  2000GB               primary
  (parted) q                                                                
  Information: You may need to update /etc/fstab.

• centos7有更简便工具：gdisk 与fdisk类似

  [root@xt ~]# gdisk /dev/sdb
  GPT fdisk (gdisk) version 0.8.10
  Partition table scan:
  MBR: protective
  BSD: not present
  APM: not present
  GPT: present
  Found valid GPT with protective MBR; using GPT. #默认是GPT模式
  Command (? for help): ?#查看帮助
  b   back up GPT data to a file
  c   change a partition‘s name
  d   delete a partition
  i   show detailed information on a partition
  l   list known partition types
  n   add a new partition
  o   create a new empty GUID partition table (GPT)
  p   print the partition table
  q   quit without saving changes
  r   recovery and transformation options (experts only)
  s   sort partitions
  t   change a partition‘s type code
  v   verify disk
  w   write table to disk and exit
  x   extra functionality (experts only)
  ?   print this menu
  ================================================
  Command (? for help): n 添加新分区
  Partition number (1-128, default 1): 
  First sector (34-6291455966, default = 2048) or {+-}size{KMGTP}: +3T
  First sector (34-6291455966, default = 2048) or {+-}size{KMGTP}: 
  Last sector (2048-6291455966, default = 6291455966) or {+-}size{KMGTP}: +3T
  Last sector (2048-6291455966, default = 6291455966) or {+-}size{KMGTP}: 
  Current type is ‘Linux filesystem‘
  Hex code or GUID (L to show codes, Enter = 8300): 8300
  Changed type of partition to ‘Linux filesystem‘
  ======查看分区信息
  Command (? for help): p
  Disk /dev/sdb: 6291456000 sectors, 2.9 TiB
  Logical sector size: 512 bytes
  Disk identifier (GUID): FA9BB121-FD84-4955-95C3-D4F21890A508
  Partition table holds up to 128 entries
  First usable sector is 34, last usable sector is 6291455966
  Partitions will be aligned on 2048-sector boundaries
  Total free space is 2014 sectors (1007.0 KiB)
  Number  Start (sector)    End (sector)  Size       Code  Name
  1            2048      6291455966   2.9 TiB     8300  Linux filesystem

• 格式化：低级格式化（分区之前进行，划分磁道）、高级格式化（分区之后对分区进行，创建文件系统）
  1.创建文件系统的工具：

  [root@xt ~]# mkfs
  mkfs.btrfs   mkfs.ext2    mkfs.ext4    mkfs.xfs     
  mkfs.cramfs  mkfs.ext3    mkfs.minix   

  2.ext系列文件系统专用管理工具：mke2fs

  mke2fs [OPTIONS]  device
              -t {ext2|ext3|ext4}：指明要创建的文件系统类型
                  mkfs.ext4 = mkfs -t ext4 = mke2fs -t ext4
              -b {1024|2048|4096}：指明文件系统的块大小；
              -L LABEL：指明卷标；
              -j：创建有日志功能的文件系统ext3；
                  mke2fs -j = mke2fs -t ext3 = mkfs -t ext3 = mkfs.ext3
              -i #：bytes-per-inode，指明inode与字节的比率；即每多少字节创建一个Indode; 
              -N #：直接指明要给此文件系统创建的inode的数量；
              -m #：指定预留的空间，百分比；               
              -O [^]FEATURE：以指定的特性创建目标文件系统； 

  3.检测及修复文件系统工具 fsck.type e2fsck xfs_repair,修复文件建议离线修复

  ext系列文件系统的专用工具：
  e2fsck : check a Linux ext2/ext3/ext4 file system
                      e2fsck [OPTIONS]  device
                          -y：对所有问题自动回答为yes; 
                          -f：即使文件系统处于clean状态，也要强制进行检测；
                          -b:superblock 超级快                           
                  fsck：check and repair a Linux file system
                      -t fstype：指明文件系统类型；
                          fsck -t ext4 = fsck.ext4
                      -a：无须交互而自动修复所有错误；
                      -r：交互式修复；   
          eg: e2fsck -v -y -b 163840 /dev/sdb7    当fsck修复不了时，使用该命令修复

  4.查看文件系统属性
  dumpe2fs, tune2fs ，xfs_info

• 挂载
  创建好文件系统后要使用先得挂载：根文件系统这外的其它文件系统要想能够被访问，都必须通过“关联”至根文件系统上的某个目录来实现，此关联操作即为“挂载”；此目录即为“挂载点”；
  1.挂载点：
  事先必须存在
  该使用未被或不会被其它进程使用到的目录
  工作目录非空，原有文件会被覆盖隐藏
  2.查看当前挂载情况
  mount
  cat /etc/mtab
  cat /proc/mounts

  3.mount挂载命令使用
  mount [-nrw] [-t vfstype] [-o options] device dir

  命令选项：
                  -r：readonly，只读挂载； 
                  -w：read and write, 读写挂载； 
                  -n：默认设备挂载或卸载的操作会同步更新至/etc/mtab文件中；-n用于禁止此特性；
                  -a:读取/etc/fstab中没有挂载的设备， mount all filesystems mentioned in fstab
                  -t vfstype：指明要挂载的设备上的文件系统的类型；可省略，会通过blkid来判断挂载设备的文件系统类型；            
  -o options：挂载选项
                  sync/async：同步/异步操作；
                  atime/noatime：文件或目录在被访问时是否更新其访问时间戳；
                  diratime/nodiratime：目录在被访问时是否更新其访问时间戳；
                  remount：重新挂载； 
                  acl：支持使用facl功能；
                      # mount -o acl  device dir 
                      # tune2fs  -o  acl  device 
                      mount -o remount,acl /dev/sda3 /mnt
                  ro：只读 
                  rw：读写 
                  dev/nodev：此设备上是否允许创建设备文件；
                  exec/noexec：是否允许运行此设备上的程序文件；
                  auto/noauto：
                  user/nouser：是否允许普通用户挂载此文件系统；
                  suid/nosuid：是否允许程序文件上的suid和sgid特殊权限生效；      
                  defaults：Use default options: rw, suid, dev, exec, auto, nouser, async, and relatime.

  4.umount卸载命令
  umount device|mount_point
  注：当正在被某进程访问时无法卸载
  查看被谁占用
  #lsof mount_point
  #fuser -v mount_point
  终止进程 访问：
  fuser -km mount_point

• 如何开机自动挂载:
  把设备信息写入到配置文件：/etc/fstab
  mount -a：可自动挂载定义在此文件中的所支持自动挂载的设备

  # /etc/fstab
  # Created by anaconda on Fri Jun  1 22:10:52 2018
  #
  # Accessible filesystems, by reference, are maintained under ‘/dev/disk‘
  # See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
  #
  UUID=9633c392-6fa0-4e3b-814d-9a2c30c60085 /                       xfs     defaults        0 0
  UUID=402d2bec-0b46-4654-8c96-6d2ca74e5668 /boot                   btrfs   subvol=boot     0 0
  UUID=9bf9acd8-1001-4eb1-b3a6-464afb90645d swap                    swap    defaults        0 0
  一共6个字段：
  1.要挂载的设备，最好使用设备的UUID
  2.挂载点，swap类型特殊
  3.文件系统类型
  4.挂载选项，如同mount中options
  5.转储频率
  6.自检次序：0不检查，1首先检查，2次级检查一般对系统盘做检查，业务盘不检查即可，若检查异常导致系统无法启动

  blkid device #查看设备uuid,类型

• VMware添加一块新磁盘，不重启，fdisk -l没有显示。

1.查看主机总线号
root@node /]# ls /sys/class/scsi_host/
host0 host1 host2
2.重新扫描SCSI总线来添加设备
[root@node /]# echo "- - -" > /sys/class/scsi_host/host0/scan
[root@node /]# echo "- - -" > /sys/class/scsi_host/host1/scan
[root@node /]# echo "- - -" > /sys/class/scsi_host/host2/scan
3.重新查看

[root@xt ~]# fdisk -l
Disk /dev/sda: 21.5 GB, 21474836480 bytes, 41943040 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: 0x00036ca6
   Device Boot      Start         End      Blocks   Id  System
/dev/sda1            2048    20973567    10485760   83  Linux
/dev/sda2        20973568    25167871     2097152   82  Linux swap / Solaris
/dev/sda3        25167872    25692159      262144   83  Linux
Disk /dev/sdb: 3221.2 GB, 3221225472000 bytes, 6291456000 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磁盘管理及文件系统使用

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原文地址：http://blog.51cto.com/12580678/2340391