linux 磁盘基础

一、fdisk工具使用

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[root@luoahong-nb ~]# fdisk -l|grep 'sd[a-c]:' Disk /dev/sda: 10.7 GB, 10737418240 bytes Disk /dev/sdb: 106 MB, 106954752 bytes Disk /dev/sdc: 106 MB, 106954752 bytes      n   创建分区        d   删除分区        p   显示分区信息    q   退出不保存      w   退出并保存                         100M 30M主分区  30M逻辑分区 Command (m for help): p   Disk /dev/sdb: 106 MB, 106954752 bytes 64 heads, 32 sectors/track, 102 cylinders, total 208896 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 identifier: 0x6d033dc2      Device Boot      Start         End      Blocks   Id  System   Command (m for help): n Command action    e   extended    p   primary partition (1-4) p Partition number (1-4): 1 First sector (2048-208895, default 2048): Using default value 2048 Last sector, +sectors or +size{K,M,G} (2048-208895, default 208895): +30M   Command (m for help): p   Disk /dev/sdb: 106 MB, 106954752 bytes 64 heads, 32 sectors/track, 102 cylinders, total 208896 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 identifier: 0x6d033dc2      Device Boot      Start         End      Blocks   Id  System /dev/sdb1            2048       63487       30720   83  Linux         Command (m for help): n                             Command action    e   extended    p   primary partition (1-4) e Partition number (1-4): 2 First sector (63488-208895, default 63488): Using default value 63488 Last sector, +sectors or +size{K,M,G} (63488-208895, default 208895): Using default value 208895   Command (m for help): p   Disk /dev/sdb: 106 MB, 106954752 bytes 64 heads, 32 sectors/track, 102 cylinders, total 208896 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 identifier: 0x6d033dc2      Device Boot      Start         End      Blocks   Id  System /dev/sdb1            2048       63487       30720   83  Linux /dev/sdb2           63488      208895       72704    5  Extended      Command (m for help): w The partition table has been altered!   Calling ioctl() to re-read partition table. Syncing disks.

二、给/dev/sdb硬盘只创建一个分区，把他挂载到/mnt上面

1.分区

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Command (m for help): n Command action e extended p primary partition (1-4) p Partition number (1-4): 1 First sector (2048-208895, default 2048): Using default value 2048 Last sector, +sectors or +size{K,M,G} (2048-208895, default 208895): Using default value 208895   Command (m for help): p   Disk /dev/sdb: 106 MB, 106954752 bytes 64 heads, 32 sectors/track, 102 cylinders, total 208896 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 identifier: 0x6d033dc2   Device Boot Start End Blocks Id System /dev/sdb1 2048 208895 103424 83 Linux   Command (m for help): w The partition table has been altered!   Calling ioctl() to re-read partition table. Syncing disks.

2.通知系统/dev/sdb硬盘的磁盘分区表变化了

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1	partprobe /dev/sdb

3.格式化创建文件系统

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[root@luoahong-nb ~]# #make filesystem [root@luoahong-nb ~]# mkfs.ext4 /dev/sdb1 mke2fs 1.41.12 (17-May-2010) Filesystem label= OS type: Linux Block size=1024 (log=0) Fragment size=1024 (log=0) Stride=0 blocks, Stripe width=0 blocks 25896 inodes, 103424 blocks 5171 blocks (5.00%) reserved for the super user First data block=1 Maximum filesystem blocks=67371008 13 block groups 8192 blocks per group, 8192 fragments per group 1992 inodes per group Superblock backups stored on blocks: 8193, 24577, 40961, 57345, 73729   Writing inode tables: done Creating journal (4096 blocks): done Writing superblocks and filesystem accounting information: done   This filesystem will be automatically checked every 36 mounts or 180 days, whichever comes first. Use tune2fs -c or -i to override.

4.关闭磁盘分区的自动检查

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[root@luoahong-nb ~]# tune2fs -c 0 -i 0 /dev/sdb1 tune2fs 1.41.12 (17-May-2010) Setting maximal mount count to -1 Setting interval between checks to 0 seconds   #-c 0 count 关闭每挂载多少次进行磁盘检查的功能 #-i 0 interval 关闭每个180天进行磁盘检查功能

5.进行磁盘分区挂载

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[root@luoahong-nb ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/sda3 8.8G 8.8G 0 100% / tmpfs 1.9G 0 1.9G 0% /dev/shm /dev/sda1 190M 40M 141M 22% /boot [root@luoahong-nb ~]# [root@luoahong-nb ~]# mount /dev/sdb1 /mnt/   [root@luoahong-nb ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/sda3 8.8G 8.8G 0 100% / tmpfs 1.9G 0 1.9G 0% /dev/shm /dev/sda1 190M 40M 141M 22% /boot /dev/sdb1 94M 1.6M 88M 2% /mnt

6.进行永久挂载（如何在开机的时候自动挂载）

方法 1./etc/rc.local

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1	/bin/mount /dev/sdb1 /mnt/

方法 2./etc/fstab

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UUID=6b8ba13d-2833-49be-8206-deb002d2d523 / ext4 defaults 1 1 UUID=e01d5cbd-b233-44b9-832d-15225cc4d8ff /boot ext4 defaults 1 2 UUID=7c5f5672-9c30-444c-a273-1350c6a06130 swap swap defaults 0 0   #/dev/sdb1 /mnt ext4 defaults 0 0   #man fstab

三、parted 

1、分区

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p[rint] 显示磁盘分区表信息 mklabel 创建磁盘分区表 gpt msdos(mbr) mkpart 创建分区 rm     删除分区 q      退出不保存   创建30M 30M   (parted) p Error: /dev/sdc: unrecognised disk label                                  (parted) mklabel gpt (parted) p                                                                Model: VMware, VMware Virtual S (scsi) Disk /dev/sdc: 107MB Sector size (logical/physical): 512B/512B Partition Table: gpt   Number  Start  End  Size  File system  Name  Flags   (parted) mkpart primary  0 30 Warning: The resulting partition is not properly aligned for best performance. Ignore/Cancel? I (parted) p                                                                Model: VMware, VMware Virtual S (scsi) Disk /dev/sdc: 107MB Sector size (logical/physical): 512B/512B Partition Table: gpt   Number  Start   End     Size    File system  Name     Flags  1      17.4kB  30.0MB  30.0MB               primary (parted) mkpart primary  30  60 (parted) p                                                                Model: VMware, VMware Virtual S (scsi) Disk /dev/sdc: 107MB Sector size (logical/physical): 512B/512B Partition Table: gpt   Number  Start   End     Size    File system  Name     Flags  1      17.4kB  30.0MB  30.0MB               primary  2      30.4MB  59.8MB  29.4MB               primary

2、以上命令顺序

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parted /dev/sdc mklabel gpt parted /dev/sdc mkpart primary 0 30  Ignore parted /dev/sdc mkpart primary 30 60 parted /dev/sdc p

企业案例：java环境内存不够导致swap

创建一个文件让文件成为swap

#1.创建一个文件块

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[root@luoahong-nb ~]# dd if=/dev/zero of=/tmp/100m bs=1M count=100 100+0 records in 100+0 records out 104857600 bytes (105 MB) copied, 0.935927 s, 112 MB/s [root@luoahong-nb ~]# file /tmp/100m /tmp/100m: data

#2.变成swap

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[root@luoahong-nb ~]# mkswap /tmp/100m mkswap: /tmp/100m: warning: don't erase bootbits sectors on whole disk. Use -f to force. Setting up swapspace version 1, size = 102396 KiB no label, UUID=1b2aea27-a092-4345-806f-b95b8d33873a [root@luoahong-nb ~]# file /tmp/100m /tmp/100m: Linux/i386 swap file (new style) 1 (4K pages) size 25599 pages

#3.swap生效

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[root@luoahong-nb ~]# swapon /tmp/100m [root@luoahong-nb ~]# free -h total used free shared buffers cached Mem: 3.9G 398M 3.5G 248K 65M 134M -/+ buffers/cache: 198M 3.7G Swap: 867M 0B 867M   [root@luoahong-nb ~]# swapon -s Filename    Type    Size    Used    Priority /dev/sda2 partition 786428  0   -1 /tmp/100m file  102396  0   -2

#4.swap永久生效

###方法1. /etc/rc.local

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1	swapon /tmp/100m

###方法2. /etc/fstab

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1	#/tmp/100m swap swap defaults 0 0

查看是否成功

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[root@luoahong-nb ~]# free -h total used free shared buffers cached Mem: 3.9G 398M 3.5G 248K 65M 134M -/+ buffers/cache: 199M 3.7G Swap: 867M 0B 867M

Linux特点会把使用过的命令和数据临时存放在内存中 cache和buffer

 

磁盘常用命令大全

1、分区工具

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fdisk：磁盘分区工具 ★★★★☆ parted：磁盘分区工具 ★★★★☆  partprobe：通知系统磁盘的分区信息变化 更新内核的硬盘分区表信息 ★★★☆☆

2、tune2fs

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tune2fs：调整ext2/ext3/ext4文件系统参数 ★★☆☆☆     -c 0 count 关闭每挂载多少次进行磁盘检查 -i 0 interval 关闭每个多久进行磁盘检查 关闭磁盘分区的自动检查

3、mkfs

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mkfs：make filesystem 创建Linux文件系统 ★★★☆☆  -t 指定文件系统类型 mkfs.ext4 == mkfs -t ext4

4、dumpe2fs

dumpe2fs：显示文件系统信息 ★★☆☆☆

5、其他

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resize2fs：调整ext2/ext3/ext4文件系统大小 ★★☆☆☆   fsck：检查并修复Linux文件系统 ★★★☆☆   -a dd：转换或复制文件 ★★★☆☆ od 查看二进制文件的内容 -xa dd if=/dev/sda of=/tmp/512.bin bs=512 count=1   od -xa /tmp/512.bin   mount：挂载文件系统 ★★★★★ umount：卸载文件系统 ★★★☆☆  umount /mnt df：报告文件系统磁盘空间的使用情况 ★★★★★     mkswap：创建交换分区 ★★☆☆☆  swapon：激活交换分区 ★★☆☆☆  swapoff：关闭交换分区 ★★★☆☆     sync：刷新文件系统缓冲区 ★★☆☆☆     top iotop 查看系统的磁盘读写速度 显示出进程使用swap的情况 io input/output 输入/输出 读写 htop top升级版 iftop 查询网卡流量情况 -i 指定监视网卡