多硬盘分区管理fdisk
前言硬盘是一台计算机的必备硬件之一，计算机如何开始使用硬盘资源就要从硬盘分区说起。开始时，一台计算机只有一块硬盘，在安装Linux Ubuntu时，第一步就是对硬盘进行分区。当我们已经安装操作系统，硬盘空间不够的时候，我们需要增加新的硬盘扩大使用空间，特别是对于虚拟化的主机，这种增加新的硬盘就变得有一些不一样了，要手动进行处理。我在做测试的走进了一个误区中，一直对subpartition这个概念不太理解，纠结于sdb2p1,sdb2p1这样的分区命名。经过几次测试后，才发现，问题出现是因为对操作系统的不理解，以至于在互联网上都找找不太多相关问题的讨论。下面我就介绍一下，我的误区及如何找到正确的方法。目录[*]分区的基本知识
[*]新增硬盘分区，走入误区
[*]完成对新增硬盘分区及挂载
1. 分区的基本知识a. 硬盘分类及标识：IDE,SATA,SCSI三个大类硬盘与标识对应关系如下表所示：
装置装置在Linux内的文件名
IDE硬盘机/dev/hd
SCSI/SATA/USB硬盘机/dev/sd
USB快闪碟/dev/sd(与SATA不同)
软盘驱动器/dev/fd
打印机25针: /dev/lp
USB: /dev/usb/lp
鼠标PS2: /dev/psaux
USB: /dev/usb/mouse
当前CDROM/DVDROM/dev/cdrom
当前的鼠标/dev/mouse
上面表格摘自：http://blog.csdn.net/zollty/article/details/7001950可以看到我现在硬盘有sda标识，物理上是一个SAS硬盘，300G。~ sudo fdisk -lDisk /dev/sda: 299.4 GB, 299439751168 bytes255 heads, 63 sectors/track, 36404 cylinders, total 584843264 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0x000efd7c Device Boot Start End Blocks IdSystem/dev/sda1 2048 97656831 48827392 82Linux swap / Solaris/dev/sda2 97656832 136718335 19530752 83Linux/dev/sda3 136718336 214843335 39062500 83Linux/dev/sda4 * 214843392 215037951 97280 83Linuxb. 硬盘构成：磁头(head)，磁道(track)，磁柱(cylinder)，扇区(setor)
在互联网上可以很容易找到解释，我就不细说了。我们在分区的时修改要能看懂硬盘信息就够了。Disk /dev/sdb: 1999.3 GB, 1999307276288 bytes255 heads, 63 sectors/track, 243068 cylinders, total 3904897024 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0xf919a976硬盘信息：
/dev/sdb，1999.3 GB，255个磁头，63个磁道，243068个磁柱，3904897024个扇区。c. 硬盘的分区
关于linux硬盘的分区主要分为 基本分区（primary partion）和扩充分区(extension partion)两种，基本分区和扩充分区的数目之和不能大于4个。基本分区可以直接使用但不能再分区。扩充分区必须再进行二次分区才能使用。需要对扩充分区建立逻辑分区（logical partion），逻辑分区没有数量上限制。所以，对于新增硬盘来说，如果我们只有4个及以下的分区要求，可以直接用基本分区完成。如果1T的硬盘想分成6个区，就需要用扩充分区+逻辑分区来实现。
2. 新增硬盘分区，走入误区我现在外接了两块SATA 7200转硬盘，分为都是1T的。重新计算机可以看硬盘信息。~ sudo fdisk -lDisk /dev/sda: 299.4 GB, 299439751168 bytes255 heads, 63 sectors/track, 36404 cylinders, total 584843264 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0x000efd7c Device Boot Start End Blocks IdSystem/dev/sda1 2048 97656831 48827392 82Linux swap / Solaris/dev/sda2 97656832 136718335 19530752 83Linux/dev/sda3 136718336 214843335 39062500 83Linux/dev/sda4 * 214843392 215037951 97280 83LinuxDisk /dev/sdb: 1999.3 GB, 1999307276288 bytes255 heads, 63 sectors/track, 243068 cylinders, total 3904897024 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0xf919a976 Device Boot Start End Blocks IdSystem/dev/sdb1 20481952448511 976223232 7HPFS/NTFS/exFAT/dev/sdb2 19524485123904892927 976222208 7HPFS/NTFS/exFAT两块硬盘，分别挂载到了/dev/sdb1，/dev/sdb2。下面我们对/dev/sdb2硬盘进行处理。/dev/sdb2还没有进行分区。~ fdisk -l /dev/sdb2Disk /dev/sdb2: 999.7 GB, 999651540992 bytes255 heads, 63 sectors/track, 121534 cylinders, total 1952444416 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0x00000000Disk /dev/sdb2 doesn't contain a valid partition table注意下面是进入误区的思考：对sdb2进行磁盘分区规划：/ 50G/extends750G/ext1 150G/ext2 150G/ext3 150G/ext4 150G/ext5 150G开始进行分区~ sudo fdisk/dev/sdb2Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabelBuilding a new DOS disklabel with disk identifier 0x6e28e6e6.Changes will remain in memory only, until you decide to write them.After that, of course, the previous content won't be recoverable.Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)Command (m for help): mCommand action a toggle a bootable flag b edit bsd disklabel c toggle the dos compatibility flag d delete a partition 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)创建第一个基本分区/，大小为50G， 50*1024*1024*1024/512+2048=104859648Command (m for help): nPartition type: p primary (0 primary, 0 extended, 4 free) e extendedSelect (default p): pPartition number (1-4, default 1):Using default value 1First sector (2048-1952444415, default 2048):Using default value 2048Last sector, +sectors or +size{K,M,G} (2048-1952444415, default 1952444415): 104859648Command (m for help): pDisk /dev/sdb2: 999.7 GB, 999651540992 bytes255 heads, 63 sectors/track, 121534 cylinders, total 1952444416 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0x44198dad Device Boot Start End Blocks IdSystem/dev/sdb2p1 2048 104859648 52428800+83Linux创建第二个扩充分区750G，750*1024*1024*1024/512+104859648=1677723648Command (m for help): nPartition type: p primary (1 primary, 0 extended, 3 free) e extendedSelect (default p): ePartition number (1-4, default 2):Using default value 2First sector (104859649-1952444415, default 104859649):Using default value 104859649Last sector, +sectors or +size{K,M,G} (104859649-1952444415, default 1952444415): 1677723648Command (m for help): pDisk /dev/sdb2: 999.7 GB, 999651540992 bytes255 heads, 63 sectors/track, 121534 cylinders, total 1952444416 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0x44198dad Device Boot Start End Blocks IdSystem/dev/sdb2p1 2048 104859648 52428800+83Linux/dev/sdb2p2 1048596491677723648 786432000 5Extended创建逻辑分区1， 150G， 150*1024*1024*1024/512+104861697=419434497Command (m for help): nPartition type: p primary (1 primary, 1 extended, 2 free) l logical (numbered from 5)Select (default p): lAdding logical partition 5First sector (104861697-1677723648, default 104861697):Using default value 104861697Last sector, +sectors or +size{K,M,G} (104861697-1677723648, default 1677723648): 419434497创建逻辑分区2， 150G， 150*1024*1024*1024/512+419436546=734009346
创建逻辑分区3， 150G， 150*1024*1024*1024/512+734009346=1048582146
创建逻辑分区4， 150G， 150*1024*1024*1024/512+1048582146=1363154946
创建逻辑分区5， 150G， 150*1024*1024*1024/512+1363154946=1677723648查看分区结果Command (m for help): pDisk /dev/sdb2: 999.7 GB, 999651540992 bytes255 heads, 63 sectors/track, 121534 cylinders, total 1952444416 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0x44198dad Device Boot Start End Blocks IdSystem/dev/sdb2p1 2048 104859648 52428800+83Linux/dev/sdb2p2 1048596491677723648 786432000 5Extended/dev/sdb2p5 104861697 419434497 157286400+83Linux/dev/sdb2p6 419436546 734009346 157286400+83Linux/dev/sdb2p7 7340113951048582146 157285376 83Linux/dev/sdb2p8 10485841951363154946 157285376 83Linux/dev/sdb2p9 13631569951677723648 157283327 83Linux退出保存Command (m for help): wThe partition table has been altered!Calling ioctl() to re-read partition table.WARNING: Re-reading the partition table failed with error 22: Invalid argument.The kernel still uses the old table. The new table will be used atthe next reboot or after you run partprobe(8) or kpartx(8)Syncing disks.更新内核分区表
不用重启系统，更新内核分区表sudo partprobe用fdisk查看新建的分区~ sudo fdisk -lDisk /dev/sda: 299.4 GB, 299439751168 bytes255 heads, 63 sectors/track, 36404 cylinders, total 584843264 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0x000efd7c Device Boot Start End Blocks IdSystem/dev/sda1 2048 97656831 48827392 82Linux swap / Solaris/dev/sda2 97656832 136718335 19530752 83Linux/dev/sda3 136718336 214843335 39062500 83Linux/dev/sda4 * 214843392 215037951 97280 83LinuxDisk /dev/sdb: 1999.3 GB, 1999307276288 bytes255 heads, 63 sectors/track, 243068 cylinders, total 3904897024 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0xf919a976 Device Boot Start End Blocks IdSystem/dev/sdb1 20481952448511 976223232 7HPFS/NTFS/exFAT/dev/sdb2 19524485123904892927 976222208 7HPFS/NTFS/exFAT这个时候，相信大家已经发现问题了，新建的分区完全没有生效。对硬盘sdb2使用fdisk查看分区~ fdisk -l /dev/sdb2Disk /dev/sdb2: 999.7 GB, 999651540992 bytes255 heads, 63 sectors/track, 121534 cylinders, total 1952444416 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0x44198dad Device Boot Start End Blocks IdSystem/dev/sdb2p1 2048 104859648 52428800+83Linux/dev/sdb2p2 1048596491677723648 786432000 5Extended/dev/sdb2p5 104861697 419434497 157286400+83Linux/dev/sdb2p6 419436546 734009346 157286400+83Linux/dev/sdb2p7 7340113951048582146 157285376 83Linux/dev/sdb2p8 10485841951363154946 157285376 83Linux/dev/sdb2p9 13631569951677723648 157283327 83Linux为什么会这样的？网上查了一下，一些朋友也遇到了这样的情况。他们把sdb2p1的这种分区叫做子分区subpartition。操作系统不明白，为什么要在sdb2的分区上再创建sdb2p1子分区。但当时我也不明白，如果我想把一块新的硬盘分区后再使用应该如何进行。其实，这种纠结的想法，原于对操作系统的不了解，导致了明白的人不会出现这种错误，出现这种错误的人找不到明白的解释。跳出子分区的概念，我们应该如何操作呢！3. 完成对新增硬盘分区及挂载上面的错误在于，我们不应该对/dev/sdb2硬盘分区，而是对/dev/sdb进行分区。Disk /dev/sdb: 1999.3 GB, 1999307276288 bytes255 heads, 63 sectors/track, 243068 cylinders, total 3904897024 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0xf919a976 Device Boot Start End Blocks IdSystem/dev/sdb1 20481952448511 976223232 7HPFS/NTFS/exFAT/dev/sdb2 19524485123904892927 976222208 7HPFS/NTFS/exFAT操作系统已经把两块新增加的硬盘，识别为了/dev/sdb，这个时候我们只需要删除原有的/dev/sdb2基本分区，重建为扩充分区，然后再按要求做逻辑分区就可以了。删除sdb2分区，重建为扩充分区/dev/sdb2~ sudo fdisk /dev/sdbCommand (m for help): dPartition number (1-4): 2Command (m for help): pDisk /dev/sdb: 1999.3 GB, 1999307276288 bytes255 heads, 63 sectors/track, 243068 cylinders, total 3904897024 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0xf919a976 Device Boot Start End Blocks IdSystem/dev/sdb1 20481952448511 976223232 7HPFS/NTFS/exFATCommand (m for help): nPartition type: p primary (1 primary, 0 extended, 3 free) e extendedSelect (default p): ePartition number (1-4, default 2):Using default value 2First sector (1952448512-3904897023, default 1952448512):Using default value 1952448512Last sector, +sectors or +size{K,M,G} (1952448512-3904897023, default 3904897023):Using default value 3904897023Command (m for help): pDisk /dev/sdb: 1999.3 GB, 1999307276288 bytes255 heads, 63 sectors/track, 243068 cylinders, total 3904897024 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0xf919a976 Device Boot Start End Blocks IdSystem/dev/sdb1 20481952448511 976223232 7HPFS/NTFS/exFAT/dev/sdb2 19524485123904897023 976224256 5Extended重新规划分区：创建逻辑分区1， 150G， 150*1024*1024*1024/512+1952450560=2267023360
创建逻辑分区2， 150G， 150*1024*1024*1024/512+2267023360=2581596160
创建逻辑分区3， 150G， 150*1024*1024*1024/512+2581596160=2896168960
创建逻辑分区4， 150G， 150*1024*1024*1024/512+2896168960=3210741760
创建逻辑分区5， 150G， 150*1024*1024*1024/512+3210741760=3525314560
创建逻辑分区6， 189G， 剩余空间Command (m for help): pDisk /dev/sdb: 1999.3 GB, 1999307276288 bytes255 heads, 63 sectors/track, 243068 cylinders, total 3904897024 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0xf919a976Device Boot Start End Blocks IdSystem/dev/sdb1 20481952448511 976223232 7HPFS/NTFS/exFAT/dev/sdb2 19524485123904897023 976224256 5Extended/dev/sdb5 19524505602267023360 157286400+83Linux/dev/sdb6 22670254092581596160 157285376 83Linux/dev/sdb7 25815982092896168960 157285376 83Linux/dev/sdb8 28961710093210741760 157285376 83Linux/dev/sdb9 32107438093525314560 157285376 83Linux/dev/sdb10 35253166093904897023 189790207+83Linux保存退出Command (m for help): wThe 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 atthe next reboot or after you run partprobe(8) or kpartx(8)Syncing disks.更新内核分区表
sudo partprobe查看新建的分区ls /dev/sdbsdb sdb1 sdb10sdb2 sdb5 sdb6 sdb7 sdb8 sdb9格式化分区sudo mkfs -t ext4 /dev/sdb5sudo mkfs -t ext4 /dev/sdb6sudo mkfs -t ext4 /dev/sdb7sudo mkfs -t ext4 /dev/sdb8sudo mkfs -t ext4 /dev/sdb9sudo mkfs -t ext4 /dev/sdb10挂载分区~ sudo mount -t ext4 /dev/sdb5 /disk/sdb5~ ls /disk/sdb5lost+found查看最终的分区效果cos@delta:~$ sudo fdisk -l password for cos:Disk /dev/sda: 299.4 GB, 299439751168 bytes255 heads, 63 sectors/track, 36404 cylinders, total 584843264 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0x000efd7c Device Boot Start End Blocks IdSystem/dev/sda1 2048 97656831 48827392 82Linux swap / Solaris/dev/sda2 97656832 136718335 19530752 83Linux/dev/sda3 136718336 214843335 39062500 83Linux/dev/sda4 * 214843392 215037951 97280 83LinuxDisk /dev/sdb: 1999.3 GB, 1999307276288 bytes255 heads, 63 sectors/track, 243068 cylinders, total 3904897024 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0xf919a976 Device Boot Start End Blocks IdSystem/dev/sdb1 20481952448511 976223232 7HPFS/NTFS/exFAT/dev/sdb2 19524485123904897023 976224256 5Extended/dev/sdb5 19524505602267023360 157286400+83Linux/dev/sdb6 22670254092581596160 157285376 83Linux/dev/sdb7 25815982092896168960 157285376 83Linux/dev/sdb8 28961710093210741760 157285376 83Linux/dev/sdb9 32107438093525314560 157285376 83Linux/dev/sdb10 35253166093904897023 189790207+83Linux完成对/dev/sdb2硬盘的分区操作。希望帮助和我一样走入到误区的朋友吧。
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