Linux下文件系统创建&LVM--------CentOS 6.X

Linux下文件系统管理

分区

Linux下最常用的分区工具是fdisk操作简单，易用，但使用这个分区工具最多分区分15个。

fdisk �Cl 查看系统上所有磁盘分区信息。

fdisk �Cl /dev/sd*

[root@www ~]# fdisk -l /dev/sdb 

Disk /dev/sdb: 21.5 GB, 21474836480 bytes

255 heads, 63 sectors/track, 2610 cylinders

Units = cylinders of 16065 * 512 = 8225280bytes

Sector size (logical/physical): 512 bytes /512 bytes

I/O size (minimum/optimal): 512 bytes / 512bytes

Disk identifier: 0x07a95eb7

 

Device Boot      Start         End      Blocks  Id  System

fdisk /dev/sd*

几个常见的参数

  d   delete a partition 删除分区

  l   list known partition types 各分区类型所对应的systemID

  n   add a new partition 创建一个新分区

  p   print the partition table 打印出分区表相当于fdisk�Cl /dev/sd*

  q   quit without saving changes 不保存当前操作退出fdisk分区工具

  t   change a partition's system id改变一个分区的system ID

  w   write table to disk and exit 保存当前操作退出fdisk

创建实例

[root@www ~]# fdisk/dev/sdb 对/dev/sdb进行分区

 

WARNING: DOS-compatible mode is deprecated.It's strongly recommended to

        switch off the mode (command 'c') and change display units to

        sectors (command 'u').

 

Command (m for help): n n表示新建一个分区

Command action

  e   extended 表示扩展分区

  p   primary partition (1-4) 表示主分区

p 输入批表示创建一个主分区

Partition number (1-4): 1输入分区编号/dev/sdb1

First cylinder (1-2610, default 1):  敲回车键表示从第一个柱面开始

Using default value 1

Last cylinder, +cylinders or +size{K,M,G}(1-2610, default 2610): +5G 分区大小为5G这里也可以键入到第几柱面

 

Command (m for help): p 查看该磁盘的分区信息

 

Disk /dev/sdb: 21.5 GB, 21474836480 bytes

255 heads, 63 sectors/track, 2610 cylinders

Units = cylinders of 16065 * 512 = 8225280bytes

Sector size (logical/physical): 512 bytes /512 bytes

I/O size (minimum/optimal): 512 bytes / 512bytes

Disk identifier: 0x07a95eb7

 

    设备名称         开始柱面         结束柱面         块大小system Id 类型

   Device Boot      Start         End      Blocks  Id  System

/dev/sdb1               1         654    5253223+  83  Linux

Command (m for help): w 保存并退出

Thepartition table has been altered!

 

Callingioctl() to re-read partition table.

Syncingdisks.

查看分区操作是否写入系统内核

[root@www ~]# cat/proc/partitions

major minor #blocks  name

 

  8        0   26214400 sda

  8        1     512000 sda1

  8        2   25701376 sda2

   8      16   20971520 sdb

   8      17    5253223 sdb1

内核能读取到硬盘分区表但是有时内核会读取不到这时就使用partx命令命令如下

[root@www~]# partx -a /dev/sdb1 /dev/sdb

创建文件系统

使用mkfsmkfs.ext[2|3|4],mke2fs来进行文件系统的创建一般使用mke2fs

mkfs �Ct ext2= mkfs.ext2 = mke2fs �Ct ext2

mkfs �Ct ext3= mkfs.ext3 = mke2fs �Ct ext3

mkfs �Ct ext4= mkfs.ext4 = mke2fs �Ct ext4

mke2fs

mke2fs �Ct type Device:创建什么类型的文件系统

mke2fs �Cb{1024|2048|4096} Device 分区的块大小

[root@www ~]# mke2fs -text4 -b 2048 /dev/sdc2

mke2fs 1.41.12 (17-May-2010)

Filesystem label=

OS type: Linux

Block size=2048 (log=1)

Fragment size=2048 (log=1)

Stride=0 blocks, Stripe width=0 blocks

197880 inodes, 1578386 blocks

78919 blocks (5.00%) reserved for the superuser

First data block=0

Maximum filesystem blocks=538968064

97 block groups

16384 blocks per group, 16384 fragments pergroup

2040 inodes per group

Superblock backups stored on blocks:

         16384,49152, 81920, 114688, 147456, 409600, 442368, 802816, 1327104

 

Writing inode tables: done                           

Creating journal (32768 blocks): done

Writing superblocks and filesystemaccounting information: done

 

This filesystem will be automaticallychecked every 24 mounts or

180 days, whichever comes first.  Use tune2fs -c or -i to override.

[root@www ~]# tune2fs -l/dev/sdc2 | grep "Block size"

Block size:               2048

[root@www ~]# blkid/dev/sdc2

/dev/sdc2:UUID="ac40a50d-ddee-44b0-a6a8-481e7b33a548" TYPE="ext4"

 

mke2fs创建默认是ext2

[root@www ~]# mke2fs /dev/sdb1

mke2fs 1.41.12 (17-May-2010)

Filesystem label=

OS type: Linux

Block size=4096 (log=2)

Fragment size=4096 (log=2)

Stride=0 blocks, Stripe width=0 blocks

328656 inodes, 1313305 blocks

65665 blocks (5.00%) reserved for the superuser

First data block=0

Maximum filesystem blocks=1346371584

41 block groups

32768 blocks per group, 32768 fragments pergroup

8016 inodes per group

Superblock backups stored on blocks:

         32768,98304, 163840, 229376, 294912, 819200, 884736

 

Writing inode tables: done                           

Writing superblocks and filesystemaccounting information: done

 

This filesystem will be automaticallychecked every 24 mounts or

180 days, whichever comes first.  Use tune2fs -c or -i to override.

mke2fs配置文件/etc/mke2fs.conf

[defaults]

       base_features = sparse_super,filetype,resize_inode,dir_index,ext_attr 默认使用ext2文件系统

       blocksize = 4096 默认块大小

       inode_size = 256 

       inode_ratio = 16384

将下面的features后的赋值补充到base_features后面系统默认分区的文件系统就是ext3或ext4

[fs_types]

       ext3 = {

                features = has_journal

       }  

       ext4 = {

                features =has_journal,extent,huge_file,flex_bg,uninit_bg,dir_nlink,extra_isize

                inode_size = 256

{

 

tune2fs -l [DEVICE] 其显示的信息十分丰富

查看其块大小

[root@www ~]# tune2fs -l/dev/sdb1 | grep "Block size"

Block size:               4096

 

blkid命令查看UUID和文件系统类型

[root@www ~]# blkid /dev/sdb1

/dev/sdb1:UUID="8595c196-9c41-4bfb-8b76-4930705e6c12" TYPE="ext2"

挂载文件系统

mount �Ct type Device 挂载点

mount命令查看当前系统挂载的文件系统

[root@www ~]# mount

/dev/mapper/vg_centos-lv_root on / typeext4 (rw)

proc on /proc type proc (rw)

sysfs on /sys type sysfs (rw)

devpts on /dev/pts type devpts(rw,gid=5,mode=620)

tmpfs on /dev/shm type tmpfs (rw)

/dev/sda1 on /boot type ext4 (rw)

none on /proc/sys/fs/binfmt_misc typebinfmt_misc (rw)

sunrpc on /var/lib/nfs/rpc_pipefs typerpc_pipefs (rw)

nfsd on /proc/fs/nfsd type nfsd (rw)

/etc/mtab文件也可以查看当前系统的挂载情况mount命令所看到的结果均来自此文件

[root@www ~]# cat/etc/mtab

/dev/mapper/vg_centos-lv_root / ext4 rw 0 0

proc /proc proc rw 0 0

sysfs /sys sysfs rw 0 0

devpts /dev/pts devpts rw,gid=5,mode=620 00

tmpfs /dev/shm tmpfs rw 0 0

/dev/sda1 /boot ext4 rw 0 0

none /proc/sys/fs/binfmt_misc binfmt_miscrw 0 0

sunrpc /var/lib/nfs/rpc_pipefs rpc_pipefsrw 0 0

nfsd /proc/fs/nfsd nfsd rw 0 0

使用mount命令挂载当时有效，系统重启失效将要挂载的文件系统吸入/etc/fstab文件中

LVM

LVM是逻辑盘卷管理Logical VolumeManager，它是Linux环境下对磁盘分区进行管理的一种机制，LVM是建立在硬盘和分区之上的一个逻辑层，来提高磁盘分区管理的灵活性

LVM创建顺序是PV――〉VG――〉LV 不知道大家注意没有使用默认安装CentOS时系统默认使用的LVM

创建前准备

将分区的system ID改成8e(Linux LVM)

[root@www ~]# fdisk/dev/sdc

 

Command (m for help): t

Partition number (1-4): 2

Hex code (type L to list codes): 8e

Changed system type of partition 2 to 8e(Linux LVM)

 

Command (m for help): p

 

Disk /dev/sdc: 21.5 GB, 21474836480 bytes

255 heads, 63 sectors/track, 2610 cylinders

Units = cylinders of 16065 * 512 = 8225280bytes

Sector size (logical/physical): 512 bytes /512 bytes

I/O size (minimum/optimal): 512 bytes / 512bytes

Disk identifier: 0xbeaf1b91

 

  Device Boot      Start         End      Blocks  Id  System

/dev/sdc1               1         654    5253223+  83  Linux

/dev/sdc2             655        1047    3156772+  8e  Linux LVM

LVM的创建流程

1. pvcreate Device

[root@www ~]# pvcreate/dev/sdc2

 Physical volume "/dev/sdc2" successfully created

[root@www ~]# pvcreate/dev/sdb1

 Physical volume "/dev/sdb1" successfully created

2. [root@www ~]# vgcreate testvg/dev/sdb1 /dev/sdc2

 Volume group "testvg" successfully created

3. [root@www ~]# lvcreate -L 5G -ntestlv testvg

 Logical volume "testlv" created

验证lv创建起没有

[root@www ~]# lvdisplay/dev/testvg/testlv

  ---Logical volume ---

  LVPath                /dev/testvg/testlv

  LV Name               testlv

  VG Name                testvg

  LVUUID                UiuqXG-22fG-qKoz-dFzw-oHvP-OZYY-aOII0F

  LVWrite Access        read/write

  LVCreation host, time www.linux.com, 2014-09-26 20:21:14 +0800

  LVStatus              available

  #open                 0

  LVSize                5.00 GiB

 Current LE             1280

 Segments               1

 Allocation             inherit

 Read ahead sectors     auto

  -currently set to     256

 Block device           253:2

创建文件系统

[root@www ~]# mke2fs -text4 /dev/testvg/testlv

挂载文件系统

1. [root@www ~]# mount -t ext4 /dev/testvg/testlv /mnt

2. [root@www ~]# mount

/dev/mapper/vg_centos-lv_rooton / type ext4 (rw)

procon /proc type proc (rw)

sysfson /sys type sysfs (rw)

devptson /dev/pts type devpts (rw,gid=5,mode=620)

tmpfson /dev/shm type tmpfs (rw)

/dev/sda1on /boot type ext4 (rw)

noneon /proc/sys/fs/binfmt_misc type binfmt_misc (rw)

sunrpcon /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)

nfsdon /proc/fs/nfsd type nfsd (rw)

gvfs-fuse-daemonon /root/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev)

/dev/sr0on /media/CentOS_6.4_Final type iso9660(ro,nosuid,nodev,uhelper=udisks,uid=0,gid=0,iocharset=utf8,mode=0400,dmode=0500)

/dev/mapper/testvg-testlvon /mnt type ext4 (rw)

LVM详细使用介绍

vg

1. vg卷组扩容

准备一个pv

[root@www ~]# pvcreate /dev/sdb2

 Physical volume "/dev/sdb2" successfully created

扩展vg的容量

使用vgextend 命令  vgextend vgname Device

[root@www ~]# vgextendtestvg /dev/sdb2

 Volume group "testvg" successfully extended

[root@www ~]# vgs

 Couldn't find device with uuid 2QpQ6S-B9Oz-7PB1-fIKo-Lhdw-h00t-3EtX00.

 VG        #PV #LV #SN Attr   VSize VFree

 VG          2   0   0wz-pn-  8.02g  8.02g

  testvg      3  1   0 wz--n- 15.02g 10.02g

 vg_centos   1   2   0wz--n- 24.51g     0

2. vg卷组的缩减

将要移除pv上的数据移动到其他pv上去

[root@www ~]# pvmove/dev/sdb1

 /dev/sdb1: Moved: 0.1%

 /dev/sdb1: Moved: 64.8%

 /dev/sdb1: Moved: 100.0%

vgreduce命令缩减vg   vgreduce vgname Device

[root@www ~]# vgreducetestvg /dev/sdb1

 Removed "/dev/sdb1" from volume group "testvg"

3. 删除vg卷组

[root@www ~]# vgremove testvg

 Volume group "testvg" successfully removed

lv

lv的扩展

首先确定lv所在的卷组的空间是不是足够多

1. 扩展物理边界

[root@www ~]# lvextend -L+2G /dev/testvg/testlv

 Extending logical volume testlv to 7.00 GiB

 Logical volume testlv successfully resized

2. 扩展逻辑边界

[root@www ~]# resize2fs/dev/testvg/testlv

resize2fs 1.41.12 (17-May-2010)

Filesystem at /dev/testvg/testlv is mountedon /mnt; on-line resizing required

old desc_blocks = 1, new_desc_blocks = 1

Performing an on-line resize of/dev/testvg/testlv to 1835008 (4k) blocks.

The filesystem on /dev/testvg/testlv is now1835008 blocks long.

3. 验证lv扩展成功没

[root@www ~]# df -lh

Filesystem            Size  Used Avail Use% Mounted on

/dev/mapper/vg_centos-lv_root

                       23G   17G 4.2G  81% /

tmpfs                 935M    0  935M   0% /dev/shm

/dev/sda1             485M   47M 414M  11% /boot

/dev/mapper/testvg-testlv

                      6.9G  140M 6.5G   3% /mnt

lv缩减

缩减lv之前一定要将其卸载并强行检测文件系统

[root@www ~]# umount/dev/testvg/testlv

[root@www ~]# fsck -f /dev/testvg/testlvfsck 是文件系统检测工具加上 �Cf 参数表示强制检测

fsck from util-linux-ng 2.17.2

e2fsck 1.41.12 (17-May-2010)

Pass 1: Checking inodes, blocks, and sizes

Pass 2: Checking directory structure

Pass 3: Checking directory connectivity

Pass 4: Checking reference counts

Pass 5: Checking group summary information

/dev/mapper/testvg-testlv: 12/458752 files(0.0% non-contiguous), 64448/1835008 blocks

如果不检测文件系统在以后使用过程中可能会产生乱码

1. 缩减逻辑卷

resizefs Device size

[root@www ~]# resize2fs/dev/testvg/testlv 5G

resize2fs 1.41.12 (17-May-2010)

Resizing the filesystem on/dev/testvg/testlv to 1310720 (4k) blocks. 

2. 缩减物理卷

[root@www ~]# lvreduce -L5G /dev/testvg/testlv

WARNING: Reducing active logical volume to 5.00 GiB

THIS MAY DESTROY YOUR DATA (filesystem etc.)

Do you really want to reduce testlv? [y/n]:y

Reducing logical volume testlv to 5.00 GiB

Logical volume testlv successfully resized

3. 移除lv卷

a)卸载lv卷mount 

b)使用lvremove Device移除lv卷

[root@www ~]# umount /mnt

[root@www ~]# lvremove/dev/testvg/testlv

Do you really want toremove active logical volume testlv? [y/n]: y

  Logical volume"testlv" successfully removed

验证

[root@www ~]# lvs

 Couldn't find device with uuid 2QpQ6S-B9Oz-7PB1-fIKo-Lhdw-h00t-3EtX00.

 LV      VG        Attr      LSize Pool Origin Data%  Move LogCpy%Sync Convert

 lv_root vg_centos -wi-ao--- 22.57g                                            

 lv_swap vg_centos -wi-ao--- 1.94g        

注意

lvreduce �CL [+|-]size Device 表示在原卷大小的基础上加或者减少多少空间

lvreduce �CL size Device 表示直接将原卷扩大多少空间。

LVM裁减顺序是 LV――〉VG――〉PV

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