分区管理工具-fdisk命令实战案例
作者：尹正杰
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fdisk工具擅长管理MBR分区。接下来我们就简单介绍一下该工具的使用。
一.分区表概述
博主推荐阅读: https://www.cnblogs.com/yinzhengjie/p/12347792.html
二.fdisk非交互式命令案例
1>.查看fidsk的帮助信息
[[email protected] ~]# fdisk -h Usage: fdisk [options]change partition table fdisk [options] -l list partition table(s) fdisk -s give partition size(s) in blocks Options: -b sector size (512, 1024, 2048 or 4096) -c[= ] compatible mode: 'dos' or 'nondos' (default) -h print this help text -u[= ] display units: 'cylinders' or 'sectors' (default) -v print program version -C specify the number of cylinders -H specify the number of heads -S specify the number of sectors per track [[email protected] ~]#
[[email protected] ~]# man fdisk #使用man手册查看fdisk查看的信息更全面。
2>.查看所有磁盘的分区表信息
[[email protected] ~]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 2T 0 disk ├─sda1 8:1 0 2M 0 part ├─sda2 8:2 0 1G 0 part /boot └─sda3 8:3 0 2T 0 part ├─centos-root 253:0 0 500G 0 lvm / └─centos-yinzhengjie 253:1 0 1.5T 0 lvm /yinzhengjie sdb 8:16 0 600G 0 disk sdc 8:32 0 400G 0 disk sdd 8:48 0 800G 0 disk sde 8:64 0 1000G 0 disk sr0 11:0 1 1024M 0 rom [[email protected] ~]# [[email protected] ~]#
[[email protected] ~]# fdisk -l WARNING: fdisk GPT support is currently new, and therefore in an experimental phase. Use at your own discretion. Disk /dev/sda: 2199.0 GB, 2199023255552 bytes, 4294967296 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: gpt Disk identifier: 60B0BC61-D7A6-4522-972F-E8B13E38A9C1 # Start End Size Type Name 1 2048 6143 2M BIOS boot 2 6144 2103295 1G Microsoft basic 3 2103296 4294723583 2T Linux LVM Disk /dev/sdd: 859.0 GB, 858993459200 bytes, 1677721600 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/sde: 1073.7 GB, 1073741824000 bytes, 2097152000 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: 429.5 GB, 429496729600 bytes, 838860800 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/sdb: 644.2 GB, 644245094400 bytes, 1258291200 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/mapper/centos-root: 536.9 GB, 536870912000 bytes, 1048576000 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/mapper/centos-yinzhengjie: 1660.9 GB, 1660944384000 bytes, 3244032000 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 [[email protected] ~]# [[email protected] ~]#
[[email protected] ~]# cat /proc/partitions major minor #blocks name 11 0 1048575 sr0 8 0 2147483648 sda 8 1 2048 sda1 8 2 1048576 sda2 8 3 2146310144 sda3 8 48 838860800 sdd 8 64 1048576000 sde 8 32 419430400 sdc 8 16 629145600 sdb 8 17 104857600 sdb1 8 18 209715200 sdb2 8 19 1 sdb3 8 21 104857600 sdb5 8 22 83886080 sdb6 253 0 524288000 dm-0 253 1 1622016000 dm-1 [[email protected] ~]# [[email protected] ~]#
[[email protected] ~]# ll /dev/sd* brw-rw---- 1 root disk 8, 0 May 8 19:31 /dev/sda brw-rw---- 1 root disk 8, 1 May 8 19:31 /dev/sda1 brw-rw---- 1 root disk 8, 2 May 8 19:31 /dev/sda2 brw-rw---- 1 root disk 8, 3 May 8 19:31 /dev/sda3 brw-rw---- 1 root disk 8, 16 May 8 20:37 /dev/sdb brw-rw---- 1 root disk 8, 17 May 8 20:37 /dev/sdb1 brw-rw---- 1 root disk 8, 18 May 8 20:37 /dev/sdb2 brw-rw---- 1 root disk 8, 19 May 8 20:37 /dev/sdb3 brw-rw---- 1 root disk 8, 21 May 8 20:37 /dev/sdb5 brw-rw---- 1 root disk 8, 22 May 8 20:37 /dev/sdb6 brw-rw---- 1 root disk 8, 32 May 8 16:33 /dev/sdc brw-rw---- 1 root disk 8, 48 May 8 16:33 /dev/sdd brw-rw---- 1 root disk 8, 64 May 8 16:33 /dev/sde [[email protected] ~]#
3>.查看单个磁盘的分区信息
[[email protected] ~]# lsblk /dev/sda NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 2T 0 disk ├─sda1 8:1 0 2M 0 part ├─sda2 8:2 0 1G 0 part /boot └─sda3 8:3 0 2T 0 part ├─centos-root 253:0 0 500G 0 lvm / └─centos-yinzhengjie 253:1 0 1.5T 0 lvm /yinzhengjie [[email protected] ~]# [[email protected] ~]#
[[email protected] ~]# fdisk -l /dev/sda WARNING: fdisk GPT support is currently new, and therefore in an experimental phase. Use at your own discretion. Disk /dev/sda: 2199.0 GB, 2199023255552 bytes, 4294967296 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: gpt Disk identifier: 60B0BC61-D7A6-4522-972F-E8B13E38A9C1 # Start End Size Type Name 1 2048 6143 2M BIOS boot 2 6144 2103295 1G Microsoft basic 3 2103296 4294723583 2T Linux LVM [[email protected] ~]# [[email protected] ~]#
三.fdisk交互式命令
[[email protected] ~]# fdisk /dev/sdb Welcome to fdisk (util-linux 2.23.2). Changes will remain in memory only, until you decide to write them. #这里提示咱们更改只会写入到内存，直到发送了写的指令才会将更改写入到磁盘设备。 Be careful before using the write command. Device does not contain a recognized partition table Building a new DOS disklabel with disk identifier 0x134e9c3c. Command (m for help):
1>.查看帮助信息
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 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 o create a new empty DOS partition table p print the partition table q quit without saving changes s create a new empty Sun disklabel t change a partition's system id u change display/entry units v verify the partition table w write table to disk and exit x extra functionality (experts only) Command (m for help):
2>.创建新的分区
Command (m for help): n Partition type: p primary (0 primary, 0 extended, 4 free) e extended Select (default p): p #我们可以不输入p，因为默认就是p选项,即主分区 Partition number (1-4, default 1): #注意哈，此处如果不输入编号默认分配编号"1" First sector (2048-1258291199, default 2048): #这里的扇区默认是2048 Using default value 2048 Last sector, +sectors or +size{K,M,G} (2048-1258291199, default 1258291199): +100G #注意哈，如果不加单位的话默认是以扇区为单位开始分配空间，因此通常分配时我们按G来分配哟~ Partition 1 of type Linux and of size 100 GiB is set Command (m for help): Command (m for help): p Disk /dev/sdb: 644.2 GB, 644245094400 bytes, 1258291200 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: 0x7bc495c7 Device Boot Start End Blocks Id System #从左到右的每个字段分别为设备名,起始扇区,结束扇区,块数量,分区的系统ID,分区的系统ID对应的类型 /dev/sdb1 2048 209717247 104857600 83 Linux Command (m for help):
Command (m for help): n Partition type: p primary (1 primary, 0 extended, 3 free) e extended Select (default p): Using default response p Partition number (2-4, default 2): First sector (209717248-1258291199, default 209717248): Using default value 209717248 Last sector, +sectors or +size{K,M,G} (209717248-1258291199, default 1258291199): +200G Partition 2 of type Linux and of size 200 GiB is set Command (m for help): Command (m for help): p Disk /dev/sdb: 644.2 GB, 644245094400 bytes, 1258291200 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: 0x7bc495c7 Device Boot Start End Blocks Id System /dev/sdb1 2048 209717247 104857600 83 Linux /dev/sdb2 209717248 629147647 209715200 83 Linux Command (m for help): Command (m for help):
Command (m for help): n Partition type: p primary (2 primary, 0 extended, 2 free) e extended Select (default p): e Partition number (3,4, default 3): First sector (629147648-1258291199, default 629147648): Using default value 629147648 Last sector, +sectors or +size{K,M,G} (629147648-1258291199, default 1258291199): +256G Partition 3 of type Extended and of size 256 GiB is set Command (m for help): Command (m for help): p Disk /dev/sdb: 644.2 GB, 644245094400 bytes, 1258291200 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: 0x7bc495c7 Device Boot Start End Blocks Id System /dev/sdb1 2048 209717247 104857600 83 Linux /dev/sdb2 209717248 629147647 209715200 83 Linux /dev/sdb3 629147648 1166018559 268435456 5 Extended Command (m for help):
Command (m for help): p Disk /dev/sdb: 644.2 GB, 644245094400 bytes, 1258291200 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: 0x7bc495c7 Device Boot Start End Blocks Id System /dev/sdb1 2048 209717247 104857600 83 Linux /dev/sdb2 209717248 629147647 209715200 83 Linux /dev/sdb3 629147648 1166018559 268435456 5 Extended Command (m for help): Command (m for help): n Partition type: p primary (2 primary, 1 extended, 1 free) l logical (numbered from 5) #当我们创建好扩展分区后，再次创建分区时会提示咱们是否创建逻辑分区,设备数字编号默认从5开始。 Select (default p): l Adding logical partition 5 First sector (629149696-1166018559, default 629149696): Using default value 629149696 Last sector, +sectors or +size{K,M,G} (629149696-1166018559, default 1166018559): +50G Partition 5 of type Linux and of size 50 GiB is set Command (m for help): Command (m for help): p Disk /dev/sdb: 644.2 GB, 644245094400 bytes, 1258291200 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: 0x7bc495c7 Device Boot Start End Blocks Id System /dev/sdb1 2048 209717247 104857600 83 Linux /dev/sdb2 209717248 629147647 209715200 83 Linux /dev/sdb3 629147648 1166018559 268435456 5 Extended /dev/sdb5 629149696 734007295 52428800 83 Linux Command (m for help):
Command (m for help): p Disk /dev/sdb: 644.2 GB, 644245094400 bytes, 1258291200 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: 0x7bc495c7 Device Boot Start End Blocks Id System /dev/sdb1 2048 209717247 104857600 83 Linux /dev/sdb2 209717248 629147647 209715200 83 Linux /dev/sdb3 629147648 1166018559 268435456 5 Extended /dev/sdb5 629149696 734007295 52428800 83 Linux Command (m for help): Command (m for help): n Partition type: p primary (2 primary, 1 extended, 1 free) l logical (numbered from 5) Select (default p): l Adding logical partition 6 First sector (734009344-1166018559, default 734009344): Using default value 734009344 Last sector, +sectors or +size{K,M,G} (734009344-1166018559, default 1166018559): +100G Partition 6 of type Linux and of size 100 GiB is set Command (m for help): Command (m for help): p Disk /dev/sdb: 644.2 GB, 644245094400 bytes, 1258291200 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: 0x7bc495c7 Device Boot Start End Blocks Id System /dev/sdb1 2048 209717247 104857600 83 Linux /dev/sdb2 209717248 629147647 209715200 83 Linux /dev/sdb3 629147648 1166018559 268435456 5 Extended /dev/sdb5 629149696 734007295 52428800 83 Linux /dev/sdb6 734009344 943724543 104857600 83 Linux Command (m for help):
Command (m for help): p Disk /dev/sdb: 644.2 GB, 644245094400 bytes, 1258291200 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: 0x7bc495c7 Device Boot Start End Blocks Id System /dev/sdb1 2048 209717247 104857600 83 Linux /dev/sdb2 209717248 629147647 209715200 83 Linux /dev/sdb3 629147648 1166018559 268435456 5 Extended /dev/sdb5 629149696 734007295 52428800 83 Linux /dev/sdb6 734009344 943724543 104857600 83 Linux Command (m for help): Command (m for help): n Partition type: p primary (2 primary, 1 extended, 1 free) l logical (numbered from 5) Select (default p): l Adding logical partition 7 First sector (943726592-1166018559, default 943726592): Using default value 943726592 Last sector, +sectors or +size{K,M,G} (943726592-1166018559, default 1166018559): +80G Partition 7 of type Linux and of size 80 GiB is set Command (m for help): Command (m for help): p Disk /dev/sdb: 644.2 GB, 644245094400 bytes, 1258291200 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: 0x7bc495c7 Device Boot Start End Blocks Id System /dev/sdb1 2048 209717247 104857600 83 Linux /dev/sdb2 209717248 629147647 209715200 83 Linux /dev/sdb3 629147648 1166018559 268435456 5 Extended /dev/sdb5 629149696 734007295 52428800 83 Linux /dev/sdb6 734009344 943724543 104857600 83 Linux /dev/sdb7 943726592 1111498751 83886080 83 Linux Command (m for help):
3>.删除分区
Command (m for help): p Disk /dev/sdb: 644.2 GB, 644245094400 bytes, 1258291200 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: 0x7bc495c7 Device Boot Start End Blocks Id System /dev/sdb1 2048 209717247 104857600 83 Linux /dev/sdb2 209717248 629147647 209715200 83 Linux /dev/sdb3 629147648 734005247 52428800 83 Linux Command (m for help): Command (m for help): d #删除分区 Partition number (1-3, default 3): #我们上面可以看到有3个分区信息，默认删除最后一个分区，我们也可以输入分区数的编号 Partition 3 is deleted Command (m for help): Command (m for help): p #删除分区后再次查看分区信息 Disk /dev/sdb: 644.2 GB, 644245094400 bytes, 1258291200 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: 0x7bc495c7 Device Boot Start End Blocks Id System /dev/sdb1 2048 209717247 104857600 83 Linux /dev/sdb2 209717248 629147647 209715200 83 Linux Command (m for help): Command (m for help):
4>.退出交互式界面
[[email protected] ~]# fdisk /dev/sdb 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): Command (m for help): q [[email protected] ~]# [[email protected] ~]#
Command (m for help): p Disk /dev/sdb: 644.2 GB, 644245094400 bytes, 1258291200 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: 0x7bc495c7 Device Boot Start End Blocks Id System /dev/sdb1 2048 209717247 104857600 83 Linux /dev/sdb2 209717248 629147647 209715200 83 Linux /dev/sdb3 629147648 1166018559 268435456 5 Extended /dev/sdb5 734009344 943724543 104857600 83 Linux /dev/sdb6 943726592 1111498751 83886080 83 Linux Command (m for help): Command (m for help): w The partition table has been altered! Calling ioctl() to re-read partition table. Syncing disks. [[email protected] ~]#
[[email protected] ~]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 2T 0 disk ├─sda1 8:1 0 2M 0 part ├─sda2 8:2 0 1G 0 part /boot └─sda3 8:3 0 2T 0 part ├─centos-root 253:0 0 500G 0 lvm / └─centos-yinzhengjie 253:1 0 1.5T 0 lvm /yinzhengjie sdb 8:16 0 600G 0 disk ├─sdb1 8:17 0 100G 0 part ├─sdb2 8:18 0 200G 0 part ├─sdb3 8:19 0 1K 0 part ├─sdb5 8:21 0 100G 0 part └─sdb6 8:22 0 80G 0 part sdc 8:32 0 400G 0 disk sdd 8:48 0 800G 0 disk sde 8:64 0 1000G 0 disk sr0 11:0 1 1024M 0 rom [[email protected] ~]# [[email protected] ~]#
[[email protected] ~]# fdisk -l /dev/sdb Disk /dev/sdb: 644.2 GB, 644245094400 bytes, 1258291200 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: 0x7bc495c7 Device Boot Start End Blocks Id System /dev/sdb1 2048 209717247 104857600 83 Linux /dev/sdb2 209717248 629147647 209715200 83 Linux /dev/sdb3 629147648 1166018559 268435456 5 Extended /dev/sdb5 734009344 943724543 104857600 83 Linux /dev/sdb6 943726592 1111498751 83886080 83 Linux [[email protected] ~]# [[email protected] ~]#
5>.修改分区的系统ID
Command (m for help): p Disk /dev/sdb: 644.2 GB, 644245094400 bytes, 1258291200 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: 0x7bc495c7 Device Boot Start End Blocks Id System /dev/sdb1 2048 209717247 104857600 83 Linux /dev/sdb2 209717248 629147647 209715200 83 Linux /dev/sdb3 629147648 1166018559 268435456 5 Extended /dev/sdb5 734009344 943724543 104857600 83 Linux /dev/sdb6 943726592 1111498751 83886080 83 Linux Command (m for help): Command (m for help): t Partition number (1-3,5,6, default 6): Hex code (type L to list all codes): l 0 Empty 24 NEC DOS 81 Minix / old Lin bf Solaris 1 FAT12 27 Hidden NTFS Win 82 Linux swap / So c1 DRDOS/sec (FAT- 2 XENIX root 39 Plan 9 83 Linux c4 DRDOS/sec (FAT- 3 XENIX usr 3c PartitionMagic 84 OS/2 hidden C: c6 DRDOS/sec (FAT- 4 FAT16 <32M 40 Venix 80286 85 Linux extended c7 Syrinx 5 Extended 41 PPC PReP Boot 86 NTFS volume set da Non-FS data 6 FAT16 42 SFS 87 NTFS volume set db CP/M / CTOS / . 7 HPFS/NTFS/exFAT 4d QNX4.x 88 Linux plaintext de Dell Utility 8 AIX 4e QNX4.x 2nd part 8e Linux LVM df BootIt 9 AIX bootable 4f QNX4.x 3rd part 93 Amoeba e1 DOS access a OS/2 Boot Manag 50 OnTrack DM 94 Amoeba BBT e3 DOS R/O b W95 FAT32 51 OnTrack DM6 Aux 9f BSD/OS e4 SpeedStor c W95 FAT32 (LBA) 52 CP/M a0 IBM Thinkpad hi eb BeOS fs e W95 FAT16 (LBA) 53 OnTrack DM6 Aux a5 FreeBSD ee GPT f W95 Ext'd (LBA) 54 OnTrackDM6 a6 OpenBSD ef EFI (FAT-12/16/ 10 OPUS 55 EZ-Drive a7 NeXTSTEP f0 Linux/PA-RISC b 11 Hidden FAT12 56 Golden Bow a8 Darwin UFS f1 SpeedStor 12 Compaq diagnost 5c Priam Edisk a9 NetBSD f4 SpeedStor 14 Hidden FAT16 <3 61 SpeedStor ab Darwin boot f2 DOS secondary 16 Hidden FAT16 63 GNU HURD or Sys af HFS / HFS+ fb VMware VMFS 17 Hidden HPFS/NTF 64 Novell Netware b7 BSDI fs fc VMware VMKCORE 18 AST SmartSleep 65 Novell Netware b8 BSDI swap fd Linux raid auto 1b Hidden W95 FAT3 70 DiskSecure Mult bb Boot Wizard hid fe LANstep 1c Hidden W95 FAT3 75 PC/IX be Solaris boot ff BBT 1e Hidden W95 FAT1 80 Old Minix Hex code (type L to list all codes): 8e Changed type of partition 'Linux' to 'Linux LVM' Command (m for help): Command (m for help): p Disk /dev/sdb: 644.2 GB, 644245094400 bytes, 1258291200 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: 0x7bc495c7 Device Boot Start End Blocks Id System /dev/sdb1 2048 209717247 104857600 83 Linux /dev/sdb2 209717248 629147647 209715200 83 Linux /dev/sdb3 629147648 1166018559 268435456 5 Extended /dev/sdb5 734009344 943724543 104857600 83 Linux /dev/sdb6 943726592 1111498751 83886080 8e Linux LVM Command (m for help):
四.分区的注意事项
1>.设备分区数字编号不稳定
生产环境中建议大家不要使用设备编号去挂载文件，因为当我们删除一个分区后，可能会导致灾难性的事情发生。 当我们删除一个分区后，删除的分区后面的所有分区数字编号减1,这意味着你之前在"/etc/fstab"文件中挂载的所有分区可能都会出现问题。
博主推荐大家使用UUID去唯一标识设备名称，这也是红帽公司在开源的Linux发行版如此设计的。
Command (m for help): p Disk /dev/sdb: 644.2 GB, 644245094400 bytes, 1258291200 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: 0x7bc495c7 Device Boot Start End Blocks Id System /dev/sdb1 2048 209717247 104857600 83 Linux /dev/sdb2 209717248 629147647 209715200 83 Linux /dev/sdb3 629147648 1166018559 268435456 5 Extended /dev/sdb5 629149696 734007295 52428800 83 Linux /dev/sdb6 734009344 943724543 104857600 83 Linux /dev/sdb7 943726592 1111498751 83886080 83 Linux Command (m for help): Command (m for help): d Partition number (1-3,5-7, default 7): 5 #我这里故意选择第五个逻辑分区进行删除。 Partition 5 is deleted Command (m for help): Command (m for help): p Disk /dev/sdb: 644.2 GB, 644245094400 bytes, 1258291200 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: 0x7bc495c7 Device Boot Start End Blocks Id System /dev/sdb1 2048 209717247 104857600 83 Linux /dev/sdb2 209717248 629147647 209715200 83 Linux /dev/sdb3 629147648 1166018559 268435456 5 Extended /dev/sdb5 734009344 943724543 104857600 83 Linux #我们发现之前数字编号5的分区的确删除了,但是其后所有分区数字均会减1 /dev/sdb6 943726592 1111498751 83886080 83 Linux Command (m for help): Command (m for help):
2>.fdisk命令查看的是磁盘上的数据
当我们为一块操作系统正在使用的磁盘进行分区时，此时可能会导致磁盘上的分区表和内存中的分区表的数据不一致的情况。这是我们需要手动将磁盘中分区表的数据同步到内存中。 在CentOS 7.x系列，使用partprobe命令就可以搞定这这件事。具体案例可参考我下面的笔记。
在CentOS 6.x系列,使用partprobe命令可能不好好使,推荐大家使用part命令,"partx -a /dev/sda"(适用于增加分区),"partx -d --nr 6 /dev/sda "(适用于删除分区所对应的编号)。
[[email protected] ~]# fdisk /dev/sda WARNING: fdisk GPT support is currently new, and therefore in an experimental phase. Use at your own discretion. 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): p Disk /dev/sda: 2199.0 GB, 2199023255552 bytes, 4294967296 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: gpt Disk identifier: 60B0BC61-D7A6-4522-972F-E8B13E38A9C1 # Start End Size Type Name 1 2048 6143 2M BIOS boot 2 6144 2103295 1G Microsoft basic 3 2103296 4294723583 2T Linux LVM Command (m for help): Command (m for help): n Partition number (4-128, default 4): First sector (34-4294967262, default 4294723584): Last sector, +sectors or +size{K,M,G,T,P} (4294723584-4294967262, default 4294967262): +1M Created partition 4 Command (m for help): w 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. [[email protected] ~]# [[email protected] ~]#
[[email protected] ~]# fdisk -l /dev/sda WARNING: fdisk GPT support is currently new, and therefore in an experimental phase. Use at your own discretion. Disk /dev/sda: 2199.0 GB, 2199023255552 bytes, 4294967296 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: gpt Disk identifier: 60B0BC61-D7A6-4522-972F-E8B13E38A9C1 # Start End Size Type Name 1 2048 6143 2M BIOS boot 2 6144 2103295 1G Microsoft basic 3 2103296 4294723583 2T Linux LVM 4 4294723584 4294725631 1M Linux filesyste [[email protected] ~]#
[[email protected] ~]# ll /dev/sda* brw-rw---- 1 root disk 8, 0 May 8 20:47 /dev/sda brw-rw---- 1 root disk 8, 1 May 8 20:47 /dev/sda1 brw-rw---- 1 root disk 8, 2 May 8 20:47 /dev/sda2 brw-rw---- 1 root disk 8, 3 May 8 20:47 /dev/sda3 [[email protected] ~]#
[[email protected] ~]# cat /proc/partitions | grep sda 8 0 2147483648 sda 8 1 2048 sda1 8 2 1048576 sda2 8 3 2146310144 sda3 [[email protected] ~]#
[[email protected] ~]# lsblk /dev/sda NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 2T 0 disk ├─sda1 8:1 0 2M 0 part ├─sda2 8:2 0 1G 0 part /boot └─sda3 8:3 0 2T 0 part ├─centos-root 253:0 0 500G 0 lvm / └─centos-yinzhengjie 253:1 0 1.5T 0 lvm /yinzhengjie [[email protected] ~]#
[[email protected] ~]# partprobe /dev/sda #该命令可以某块将磁盘中的数据同步到内存中，如果不指定磁盘，默认会将所有的磁盘设备的分区表重新刷新到内存。
[[email protected] ~]# lsblk /dev/sda NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 2T 0 disk ├─sda1 8:1 0 2M 0 part ├─sda2 8:2 0 1G 0 part /boot ├─sda3 8:3 0 2T 0 part │ ├─centos-root 253:0 0 500G 0 lvm / │ └─centos-yinzhengjie 253:1 0 1.5T 0 lvm /yinzhengjie └─sda4 8:4 0 1M 0 part [[email protected] ~]#
[[email protected] ~]# cat /proc/partitions | grep sda 8 0 2147483648 sda 8 1 2048 sda1 8 2 1048576 sda2 8 3 2146310144 sda3 8 4 1024 sda4 [[email protected] ~]#
[[email protected] ~]# ll /dev/sda* brw-rw---- 1 root disk 8, 0 May 8 20:55 /dev/sda brw-rw---- 1 root disk 8, 1 May 8 20:55 /dev/sda1 brw-rw---- 1 root disk 8, 2 May 8 20:55 /dev/sda2 brw-rw---- 1 root disk 8, 3 May 8 20:55 /dev/sda3 brw-rw---- 1 root disk 8, 4 May 8 20:55 /dev/sda4 [[email protected] ~]#
五.博主推荐阅读
gdisk工具使用案例: https://www.cnblogs.com/yinzhengjie/p/12359770.html parted工具使用案例: https://www.cnblogs.com/yinzhengjie/p/12355151.html