(图片源自网络)
一 机械硬盘
柱面cylinder:每个盘片面的同轨道数据为一个柱面,即每个磁盘的每个面同一轨道号的数据称为柱面
扇区sector:以圆心为角度扩散的区域为扇形,即为扇区
磁头head:磁臂上读取磁盘的读写头为磁头
二 磁盘表示
IDE机械硬盘 hd <a...z><1...n>:
<a...z>为第几块磁盘的顺序
<1...n>每个磁盘的分区顺序
SATA,SCSI,SAS,U盘等硬盘 sd<a...z><1...n>:
<a...z>为第几块磁盘的顺序
<1...n>每个磁盘的分区顺序
例:
有一块IDE硬盘分两个区,一块SATA硬盘分3个区
在/dev下显示如:
/dev/hda
/dev/hda1
/dev/hda2
/dev/sdb
/dev/sdb1
/dev/sdb2
/dev/sdb3
同样适用于DVD,cdrom,floppy等
三 系统分区
主要分MBR或者GPT
MBR(master boot record)传统的X86架构硬件BIOS引导的分区机制,只支持32bit或64bit系统,分区数量有限.
MBR结构占用硬盘前512字节,按顺序分为:
1.引导代码占446字节
2.分区表占64个字节,分为4条16字节
3.标记是否可引导2字节
分区限制:
主分区最大4个,(扩展分区也属于主分区只能存在一个)因为只有4条分区字节
扩展分区最大1个,会占用一个主分区数
逻辑分区无限制
GPT(GUID partition table)兼容更多架构只支持UEFI引导的分区机制,只支持64bit系统,默认支持2TB以上硬盘,
由intel发布的替代BIOS的技术,很多新主板可以切换BIOS为UEFI模式,
全局唯一标示分区表结构如下:
1.表头8字节
2.版本4字节
3.分区表大小4字节
4.分区表头校验4字节
5.保留信息4字节
6.分区表项参数(含备份表)64字节
7.分区串行校验4字节
8.保留
分区表项格式如下:
1.分区类型16字节
2.分区全局标识(GUID)16字节
3.起始LBA 8字节
4.结束LBA 8字节
5.属性标签 8字节
6.分区名 72字节
分区限制:
GPT支持分区数量,仅受操作系统限制
GPT有两个分区表,一个主要分区表,一个备份分区表
四 分区工具的使用
fdisk
fdisk -l 查看当前硬盘及分区信息
[root@localhost ~]# fdisk -l Disk /dev/sda: 21.4 GB, 21474836480 bytes 255 heads, 63 sectors/track, 2610 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sda1 * 1 13 104391 83 Linux /dev/sda2 14 2610 20860402+ 8e Linux LVM Disk /dev/sdb: 5368 MB, 5368709120 bytes 255 heads, 63 sectors/track, 652 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Disk /dev/sdb doesn't contain a valid partition table [root@localhost ~]#
fdisk /dev/sdb 进入这块磁盘分区交互界面
[root@localhost ~]# fdisk/dev/sdb bash: fdisk/dev/sdb: No such file or directory [root@localhost ~]# fdisk /dev/sdb Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel Building a new DOS disklabel. 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):
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 l list known partition types m print this menu n add a new partition #新建磁盘分区 o create a new empty DOS partition table p print the partition table #查看当前硬盘分区情况 q quit without saving changes s create a new empty Sun disklabel t change a partition's system id #修改分区ID u change display/entry units v verify the partition table w write table to disk and exit #保存并推出 x extra functionality (experts only) Command (m for help): p Disk /dev/sdb: 5368 MB, 5368709120 bytes 255 heads, 63 sectors/track, 652 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System Command (m for help): n Command action e extended #创建一个扩展分区 p primary partition (1-4) #创建一个主分区,分区号1-4 p Partition number (1-4): 1 First cylinder (1-652, default 1): Using default value 1 Last cylinder or +size or +sizeM or +sizeK (1-652, default 652): +2.5G Command (m for help): P Disk /dev/sdb: 5368 MB, 5368709120 bytes 255 heads, 63 sectors/track, 652 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sdb1 1 3 24066 83 Linux Command (m for help): n Command action e extended p primary partition (1-4) e Partition number (1-4): 2 First cylinder (4-652, default 4): Using default value 4 Last cylinder or +size or +sizeM or +sizeK (4-652, default 652): Using default value 652 Command (m for help): p Disk /dev/sdb: 5368 MB, 5368709120 bytes 255 heads, 63 sectors/track, 652 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sdb1 1 3 24066 83 Linux /dev/sdb2 4 652 5213092+ 5 Extended Command (m for help): n Command action l logical (5 or over) #创建一个逻辑分区,分区号从5开始 p primary partition (1-4) l First cylinder (4-652, default 4): Using default value 4 Last cylinder or +size or +sizeM or +sizeK (4-652, default 652): +5G Command (m for help): P Disk /dev/sdb: 5368 MB, 5368709120 bytes 255 heads, 63 sectors/track, 652 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sdb1 1 3 24066 83 Linux /dev/sdb2 4 652 5213092+ 5 Extended /dev/sdb5 4 612 4891761 83 Linux Command (m for help): n Command action l logical (5 or over) p primary partition (1-4) l First cylinder (613-652, default 613): Using default value 613 Last cylinder or +size or +sizeM or +sizeK (613-652, default 652): Using default value 652 Command (m for help): p Disk /dev/sdb: 5368 MB, 5368709120 bytes 255 heads, 63 sectors/track, 652 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sdb1 1 3 24066 83 Linux /dev/sdb2 4 652 5213092+ 5 Extended /dev/sdb5 4 612 4891761 83 Linux /dev/sdb6 613 652 321268+ 83 Linux Command (m for help): t Partition number (1-6): 1 Hex code (type L to list codes): L 0 Empty 1e Hidden W95 FAT1 80 Old Minix bf Solaris 1 FAT12 24 NEC DOS 81 Minix / old Lin c1 DRDOS/sec (FAT- 2 XENIX root 39 Plan 9 82 Linux swap / So c4 DRDOS/sec (FAT- 3 XENIX usr 3c PartitionMagic 83 Linux c6 DRDOS/sec (FAT- 4 FAT16 <32M 40 Venix 80286 84 OS/2 hidden C: c7 Syrinx 5 Extended 41 PPC PReP Boot 85 Linux extended da Non-FS data 6 FAT16 42 SFS 86 NTFS volume set db CP/M / CTOS / . 7 HPFS/NTFS 4d QNX4.x 87 NTFS volume set de Dell Utility 8 AIX 4e QNX4.x 2nd part 88 Linux plaintext df BootIt 9 AIX bootable 4f QNX4.x 3rd part 8e Linux LVM e1 DOS access a OS/2 Boot Manag 50 OnTrack DM 93 Amoeba e3 DOS R/O b W95 FAT32 51 OnTrack DM6 Aux 94 Amoeba BBT e4 SpeedStor c W95 FAT32 (LBA) 52 CP/M 9f BSD/OS eb BeOS fs e W95 FAT16 (LBA) 53 OnTrack DM6 Aux a0 IBM Thinkpad hi ee EFI GPT f W95 Ext'd (LBA) 54 OnTrackDM6 a5 FreeBSD ef EFI (FAT-12/16/ 10 OPUS 55 EZ-Drive a6 OpenBSD f0 Linux/PA-RISC b 11 Hidden FAT12 56 Golden Bow a7 NeXTSTEP f1 SpeedStor 12 Compaq diagnost 5c Priam Edisk a8 Darwin UFS f4 SpeedStor 14 Hidden FAT16 <3 61 SpeedStor a9 NetBSD f2 DOS secondary 16 Hidden FAT16 63 GNU HURD or Sys ab Darwin boot 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 Hex code (type L to list codes): 83 #分区后其实默认就是83 Command (m for help): p Disk /dev/sdb: 5368 MB, 5368709120 bytes 255 heads, 63 sectors/track, 652 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sdb1 1 3 24066 83 Linux /dev/sdb2 4 652 5213092+ 5 Extended /dev/sdb5 4 612 4891761 83 Linux /dev/sdb6 613 652 321268+ 83 Linux Command (m for help): w The partition table has been altered! Calling ioctl() to re-read partition table. Syncing disks. [root@localhost ~]#
partprobe 使内核更新磁盘信息后就能通过fdisk -l看到磁盘信息了
四 创建文件系统
俗称格式化,没有被格式化的分区为raw
mke2fs -T ext3 /dev/sdb2 创建文件系统 格式为ext3 分区为/dev/sdb1
-b "blocksize" 指定文件系统块大小(每次读写磁盘的最小大小,一般默认4096)
-c 创建时检查磁盘坏块
-L "label" 指定分区卷标
-j 建立文件系统日志 (ext3和ext4默认带)
[root@localhost mnt]# mke2fs -T ext3 /dev/sdb5 mke2fs 1.39 (29-May-2006) Filesystem label= OS type: Linux Block size=4096 (log=2) Fragment size=4096 (log=2) 306432 inodes, 612470 blocks 30623 blocks (5.00%) reserved for the super user First data block=0 Maximum filesystem blocks=629145600 19 block groups 32768 blocks per group, 32768 fragments per group 16128 inodes per group Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912 Writing inode tables: done Writing superblocks and filesystem accounting information: done This filesystem will be automatically checked every 37 mounts or 180 days, whichever comes first. Use tune2fs -c or -i to override. [root@localhost mnt]#
mkfs.ext3 /dev/sdb1 直接创建sdb1文件系统为ext3
[root@localhost ~]# mkfs.ext3 /dev/sdb1 mke2fs 1.39 (29-May-2006) Filesystem label= OS type: Linux Block size=4096 (log=2) Fragment size=4096 (log=2) 245280 inodes, 489974 blocks 24498 blocks (5.00%) reserved for the super user First data block=0 Maximum filesystem blocks=503316480 15 block groups 32768 blocks per group, 32768 fragments per group 16352 inodes per group Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912 Writing inode tables: done Creating journal (8192 blocks): done Writing superblocks and filesystem accounting information: done This filesystem will be automatically checked every 29 mounts or 180 days, whichever comes first. Use tune2fs -c or -i to override. [root@localhost ~]# mke2fs -t ext3 /dev/sdb1 mke2fs 1.39 (29-May-2006) mke2fs: invalid blocks count - /dev/sdb1
dumpe2fs /dev/sdb1 查看此分区详细信息
[root@localhost ~]# dumpe2fs /dev/sdb1 dumpe2fs 1.39 (29-May-2006) Filesystem volume name: <none> Last mounted on: <not available> Filesystem UUID: 27edd72e-c733-40de-8fa2-a280f0985180 Filesystem magic number: 0xEF53 Filesystem revision #: 1 (dynamic) Filesystem features: has_journal resize_inode dir_index filetype sparse_super large_file ....................................................
fsck /dev/sdb1 修复文件系统(修复前必须卸载磁盘)
fsck -y /dev/sdb1 不提示直接修复文件系统
mkdir /mnt/sdb1
mount /dev/sdb1 /mnt/sdb1 挂载磁盘到上面创建的目录(磁盘 挂载点)
umount /dev/sdb1 卸载分区(通过磁盘)
umount /mnt/sdb1 卸载分区(通过挂载点)
可以通过修改配置文件启动时自动挂载
修改/etc/fstab
在最后添加要挂载的信息
/dev/sdb1<tab>/mnt<tab>ext4<tab>defaults<tab>0 0
目标磁盘 挂载点 文件系统 参数1 参数2
