何為磁盤分區，為什么要分區？
計算機中存放信息的主要的存儲設備就是硬盤，但是硬盤不能直接使用，必須對硬盤進行分割，分割成的一塊一塊的硬盤區域就是磁盤分區。在傳統的磁盤管理中，將一個硬盤分為兩大類分區：主分區和擴展分區。主分區是能夠安裝操作系統，能夠進行計算機啟動的分區，這樣的分區可以直接格式化，然后安裝系統，直接存放文件。
MBR分區結構
在一個MBR分區表類型的硬盤中最多只能存在4個主分區。如果一個硬盤上需要超過4個以上的磁盤分塊的話，那么就需要使用擴展分區了。如果使用擴展分區，那么一個物理硬盤上最多只能3個主分區和1個擴展分區。擴展分區不能直接使用，它必須經過第二次分割成為一個一個的邏輯分區，然后才可以使用。一個擴展分區中的邏輯分區可以任意多個。
1、Linux磁盤分區查看
[root@centos6 ~]# fdisk -l Disk /dev/sda: 214.7 GB, 214748364800 bytes 255 heads, 63 sectors/track, 26108 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00007b7d Device Boot Start End Blocks Id System /dev/sda1 * 1 26 204800 83 Linux Partition 1 does not end on cylinder boundary. /dev/sda2 26 12774 102400000 83 Linux /dev/sda3 12774 14049 10240000 83 Linux /dev/sda4 14049 26109 96869376 5 Extended /dev/sda5 14049 14310 2097152 82 Linux swap / Solaris
/dev/sda: 214.7 GB #該sda硬盤磁盤容量為 214.7GB 214748364800 bytes：總共 214748364800 字節 255 heads：255個磁頭 63 sectors/track：一個盤面總共63個扇區 26108 cylinders：26108個柱面 Units = cylinders of 16065 * 512 = 8225280 bytes：每個柱面（cylinders ）總共有 16065個扇區，每個扇區總共 512字節，所以每個柱面總共為 16065*512 =8225280 bytes（字節） Sector size (logical/physical): 512 bytes / 512 bytes：每個扇區的邏輯和物理容量大小都為 512 bytes（字節） I/O size (minimum/optimal): 512 bytes / 512 bytes：I/O的容量最小和最佳值都為 512 bytes（字節） Disk identifier: 0x00007b7d：磁盤標識符為 0x00007b7d
Device：設備名稱 Boot：是否可引導 Start：起始柱面 End：結束柱面 Blocks：包含的磁盤塊數 Id：分區標識 System：應用在那個系統在上常用的分區標識 /dev/sda1：分區名稱 *：可引導設備 1：從第1個柱面開始 26：在第26個柱面結束 204800：磁盤塊數為204800 83：分區ID標識為83 Linux：應用在linux系統之上 /dev/sda2：分區名稱 26：從第26個柱面開始 12774：在第12774個柱面結束 102400000：磁盤塊數為102400000 83：分區ID標識為83 Linux：應用在linux系統之上 /dev/sda3：分區名稱 12774：從第12774柱面開始 14049：在第14049個柱面結束 10240000：磁盤塊數為10240000 83：分區ID標識為83 Linux：應用在linux系統之上 /dev/sda4：分區名稱 14049: 從第14049個柱面開始 26109：在第26109個柱面結束 96869376：磁盤塊數為96869376 5：分區ID標識為5 Extended：應用在linux系統擴展分區之上 /dev/sda5：分區名稱 14049：從第14049個柱面開始 14310：在第14310個柱面結束 2097152：磁盤塊數為2097152 82：分區ID標識為82 Linux swap / Solaris：應用在linux系統swap之上
2、Linux磁盤分區
fdisk 命令
簡介： fdisk - Partition table manipulator for Linux
格式： fdisk [-uc] [-b sectorsize] [-C cyls] [-H heads] [-S sects] device fdisk -l [-u] [device...] fdisk -s partition... fdisk -v fdisk -h
Command action a toggle a bootable flag #設置一個標識，說明這個分區是可啟動的 b edit bsd disklabel #編輯BSD Linux系統用的磁盤標簽 c toggle the dos compatibility flag #設置DOS兼容標識 d delete a partition #刪除分區 l list known partition types #顯示可用的分區類型 m print this menu #顯示命令先選項幫助手冊 n add a new partition #添加一個新分區 o create a new empty DOS partition table #創建DOS分區表 p print the partition table #顯示當前分區表 q quit without saving changes #退出，不保存更改 s create a new empty Sun disklabel #為Sun Linux系統創建一個新磁盤標簽 t change a partition's system id #修改分區的系統ID u change display/entry units #改變使用的存儲單元 v verify the partition table #驗證分區表 w write table to disk and exit #將分區表寫入磁盤 x extra functionality (experts only) #高級功能
實例1：
[root@centos6 ~]# fdisk /dev/sda #對sda這塊硬盤進行分區管理
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): p #查看當前分區情況
Disk /dev/sda: 214.7 GB, 214748364800 bytes
255 heads, 63 sectors/track, 26108 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00007b7d
Device Boot Start End Blocks Id System
/dev/sda1 * 1 26 204800 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 26 12774 102400000 83 Linux
/dev/sda3 12774 14049 10240000 83 Linux
/dev/sda4 14049 26109 96869376 5 Extended
/dev/sda5 14049 14310 2097152 82 Linux swap / Solaris
Command (m for help): n #創建一個新分區
First cylinder (14310-26109, default 14310): #默認以柱面進行分區，默認柱面開始值為14310，直接回車就是選擇默認值
Using default value 14310
Last cylinder, +cylinders or +size{K,M,G} (14310-26109, default 26109): 14500 #填寫結束柱面值14500
Command (m for help): p #查看以分好的區
Disk /dev/sda: 214.7 GB, 214748364800 bytes
255 heads, 63 sectors/track, 26108 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00007b7d
Device Boot Start End Blocks Id System
/dev/sda1 * 1 26 204800 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 26 12774 102400000 83 Linux
/dev/sda3 12774 14049 10240000 83 Linux
/dev/sda4 14049 26109 96869376 5 Extended
/dev/sda5 14049 14310 2097152 82 Linux swap / Solaris
/dev/sda6 14310 14500 1526194+ 83 Linux
Command (m for help): w #確認不再做任何操作，直接保存退出
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.
[root@centos6 ~]# fdisk -l #查看分區情況（真實情況）
Disk /dev/sda: 214.7 GB, 214748364800 bytes
255 heads, 63 sectors/track, 26108 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00007b7d
Device Boot Start End Blocks Id System
/dev/sda1 * 1 26 204800 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 26 12774 102400000 83 Linux
/dev/sda3 12774 14049 10240000 83 Linux
/dev/sda4 14049 26109 96869376 5 Extended
/dev/sda5 14049 14310 2097152 82 Linux swap / Solaris
/dev/sda6 14310 14500 1526194+ 83 Linux
[root@centos6 ~]# cat /proc/partitions #查看是否已寫入內核中，顯示并唯有邏輯分區/dev/sda6
major minor #blocks name
8 0 209715200 sda
8 1 204800 sda1
8 2 102400000 sda2
8 3 10240000 sda3
8 4 1 sda4
8 5 2097152 sda5
[root@centos6 ~]# partx -a /dev/sda #可用此方法讓內核掃描分區情況
BLKPG: Device or resource busy
error adding partition 1
BLKPG: Device or resource busy
error adding partition 2
BLKPG: Device or resource busy
error adding partition 3
BLKPG: Device or resource busy
error adding partition 4
BLKPG: Device or resource busy
error adding partition 5
[root@centos6 ~]# partx -a /dev/sda #如果第一次掃描未有顯示，可再次執行該命令
BLKPG: Device or resource busy
error adding partition 1
BLKPG: Device or resource busy
error adding partition 2
BLKPG: Device or resource busy
error adding partition 3
BLKPG: Device or resource busy
error adding partition 4
BLKPG: Device or resource busy
error adding partition 5
BLKPG: Device or resource busy
error adding partition 6
[root@centos6 ~]# cat /proc/partitions #查看內核是否已識別
major minor #blocks name
8 0 209715200 sda
8 1 204800 sda1
8 2 102400000 sda2
8 3 10240000 sda3
8 4 1 sda4
8 5 2097152 sda5
8 6 1526194 sda6
[root@centos6 ~]# ls /dev/sda* #也可以用此類方法查看
/dev/sda /dev/sda1 /dev/sda2 /dev/sda3 /dev/sda4 /dev/sda5 /dev/sda6
[root@centos6 ~]# lsblk #也可以用這種方法查看
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sr0 11:0 1 1024M 0 rom
sda 8:0 0 200G 0 disk
├─sda1 8:1 0 200M 0 part /boot
├─sda2 8:2 0 97.7G 0 part /
├─sda3 8:3 0 9.8G 0 part /testdir
├─sda4 8:4 0 1K 0 part
├─sda5 8:5 0 2G 0 part [SWAP]
└─sda6 8:6 0 1.5G 0 part
[root@centos6 ~]#
實例2： [root@centos6 ~]# partx -d -n 6 /dev/sda #不用fdisk命令，直接用partx命令刪除分區 [root@centos6 ~]# cat /proc/partitions major minor #blocks name 8 0 209715200 sda 8 1 204800 sda1 8 2 102400000 sda2 8 3 10240000 sda3 8 4 1 sda4 8 5 2097152 sda5
實例3:
[root@centos6 ~]# fdisk /dev/sda
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 #創建一個新分區
First cylinder (14310-26109, default 14310):
Using default value 14310 #默認起始柱面
Last cylinder, +cylinders or +size{K,M,G} (14310-26109, default 26109): 15000 #設置結束柱面為15000
Command (m for help): t #設置分區類型
Partition number (1-6): 6
Hex code (type L to list codes): 82 #設置分區類型為82，也就是swap分區
Changed system type of partition 6 to 82 (Linux swap / Solaris)
Command (m for help): p #查看分區情況
Disk /dev/sda: 214.7 GB, 214748364800 bytes
255 heads, 63 sectors/track, 26108 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00007b7d
Device Boot Start End Blocks Id System
/dev/sda1 * 1 26 204800 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 26 12774 102400000 83 Linux
/dev/sda3 12774 14049 10240000 83 Linux
/dev/sda4 14049 26109 96869376 5 Extended
/dev/sda5 14049 14310 2097152 82 Linux swap / Solaris
/dev/sda6 14310 15000 5542444+ 82 Linux swap / Solaris
Command (m for help): w #保持退出
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.
[root@centos6 ~]# partx -a /dev/sda #讓內核掃描分區
BLKPG: Device or resource busy
error adding partition 1
BLKPG: Device or resource busy
error adding partition 2
BLKPG: Device or resource busy
error adding partition 3
BLKPG: Device or resource busy
error adding partition 4
BLKPG: Device or resource busy
error adding partition 5
[root@centos6 ~]# partx -a /dev/sda
BLKPG: Device or resource busy
error adding partition 1
BLKPG: Device or resource busy
error adding partition 2
BLKPG: Device or resource busy
error adding partition 3
BLKPG: Device or resource busy
error adding partition 4
BLKPG: Device or resource busy
error adding partition 5
BLKPG: Device or resource busy
error adding partition 6
[root@centos6 ~]# lsblk #查看內核已經識別分好的分區
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sr0 11:0 1 1024M 0 rom
sda 8:0 0 200G 0 disk
├─sda1 8:1 0 200M 0 part /boot
├─sda2 8:2 0 97.7G 0 part /
├─sda3 8:3 0 9.8G 0 part /testdir
├─sda4 8:4 0 1K 0 part
├─sda5 8:5 0 2G 0 part [SWAP]
└─sda6 8:6 0 5.3G 0 part
[root@centos6 ~]# fdisk -l /dev/sda #再次查看分區情況
Disk /dev/sda: 214.7 GB, 214748364800 bytes
255 heads, 63 sectors/track, 26108 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00007b7d
Device Boot Start End Blocks Id System
/dev/sda1 * 1 26 204800 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 26 12774 102400000 83 Linux
/dev/sda3 12774 14049 10240000 83 Linux
/dev/sda4 14049 26109 96869376 5 Extended
/dev/sda5 14049 14310 2097152 82 Linux swap / Solaris
/dev/sda6 14310 15000 5542444+ 82 Linux swap / Solaris
[root@centos6 ~]#
原創文章，作者：Aleen，如若轉載，請注明出處：http://www.www58058.com/40689
