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The quality of Linux disk management is directly related to the performance of the entire system.
The three commonly used Linux disk management commands are df, du, and fdisk.
df: List the overall disk usage of the file system
du: Check disk space usage
fdisk: Used for disk partitioning
df command parameter function: Check the disk space usage of the file system. You can use this command to get how much disk space is occupied, how much space is left, and other information.
Syntax:
df [-ahikHTm] [Directory or filename]
Options and Parameters:
-a ：List all file systems, including those unique to the system /proc and other file systems
-k ：Display each file system in KBytes capacity
-m ：Display each file system in MBytes capacity
-h ：Display in formats that are easier for people to read, such as GBytes, MBytes, KBytes, etc.
-H ：Display as M=1000K instead of M=1024K's rounding method;
-T ：Display the file system type, including the filesystem name of the partition (e.g., ext3) are also listed;
-i ：Display the number of inodes instead of hard disk capacity
List all file systems within the system!
[root@www ~]# df Filesystem 1K-blocks Used Available Use% Mounted on /dev/hdc2 9920624 3823112 5585444 41% / /dev/hdc3 4956316 141376 4559108 4% /home /dev/hdc1 101086 11126 84741 12% /boot tmpfs 371332 0 371332 0% /dev/shm
Under Linux, if df is not added with any options, it will default to listing all the Also include those in special memory file systems and swap 1 List the capacity in Kbytes!
Display the capacity result in a readable capacity format
[root@www ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/hdc2 9files (5G 3files (7G 5files (4G 41% / /dev/hdc3 4files (8G 139M 4files (4G 4% /home /dev/hdc1 99M 11M 83M 12% /boot tmpfs 363M 363M /dev/shm
List all special file formats and names within the system
[root@www ~]# df -aT Filesystem 1K-blocks Used Available Use% Mounted on /dev/hdc2 ext3 9920624 3823112 5585444 41% / proc proc 0 0 0 - /proc sysfs sysfs 0 0 0 - /sys devpts devpts 0 0 0 - /dev/pts /dev/hdc3 ext3 4956316 141376 4559108 4% /home /dev/hdc1 ext3 101086 11126 84741 12% /boot tmpfs tmpfs 371332 0 371332 0% /dev/shm none binfmt_misc 0 0 0 - /proc/sys/fs/binfmt_misc sunrpc rpc_pipefs 0 0 0 - /var/lib/nfs/rpc_pipefs
将 /etc 底下的可用的磁盘容量以易读的容量格式显示
[root@www ~]# df -h /etc Filesystem Size Used Avail Use% Mounted on /dev/hdc2 9files (5G 3files (7G 5files (4G 41% /
Linux du命令也是查看使用空间的，但是与df命令不同的是Linux du命令是对文件和目录磁盘使用的空间的查看，还是和df命令有一些区别的，这里介绍Linux du命令。
Syntax:
du [-ahskm] 文件或目录名称
Options and Parameters:
-a ：列出所有的文件与目录容量，因为默认仅统计目录底下的文件量而已。
-h ：以人们较易读的容量格式 (G/M) 显示；
-s ：列出总量而已，而不列出每个各别的目录占用容量；
-S ：不包括子目录下的总计，与 -s 有点差别。
-k ：以 KBytes 列出容量显示；
-m ：以 MBytes 列出容量显示；
只列出当前目录下的所有文件夹容量（包括隐藏文件夹）:
[root@www ~]# du 8 files (/test4 <==每个目录都会列出来 8 files (/test2 ....Omitted.... 12 files (/.gconfd <==包括隐藏文件的目录 220 . <==这个目录(.)所占用的总量
When du is entered directly without any options, du will analyze the disk space occupied by the files and directories in the current directory.
List the file size as well
[root@www ~]# du -a 12 files (/install.log.syslog <==The list of files is now present 8 files (/.bash_logout 8 files (/test4 8 files (/test2 ....Omitted.... 12 files (/.gconfd 220 .
Check the capacity occupied by each directory under the root directory
[root@www ~]# du -sm /* 7 /bin 6 /boot .....Omitted in the middle..... 0 /proc .....Omitted in the middle..... 1 /tmp 3859 /usr <== It was the largest in the initial system! 77 /var
Wildcard * to represent each directory.
Unlike df, the du command actually searches all file data directly within the file system.
fdisk is a Linux disk partition table operation tool.
Syntax:
fdisk [-l] device name
Options and Parameters:
-l : Output the partition content of the device followed. If only fdisk -l when Then the system will list all partitions of all devices that can be searched within the entire system.
List all partition information
[root@AY120919111755c246621 tmp]# fdisk -l Disk /dev/xvda: 21files (5 GB, 21474836480 bytes 255 heads, 63 sectors/track, 2610 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: 0x00000000 Device Boot Start End Blocks Id System /dev/xvda1 * 1 2550 20480000 83 Linux /dev/xvda2 2550 2611 490496 82 Linux swap / Solaris Disk /dev/xvdb: 21files (5 GB, 21474836480 bytes 255 heads, 63 sectors/track, 2610 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: 0x56f40944 Device Boot Start End Blocks Id System /dev/xvdb2 1 2610 20964793+ 83 Linux
Find the disk where the root directory of your system is located and check the relevant information within the hard disk
[root@www ~]# df / <== Note: The focus is on finding the disk filename only Filesystem 1K-blocks Used Available Use% Mounted on /dev/hdc2 9920624 3823168 5585388 41% / [root@www ~]# fdisk /dev/hdc <== Look carefully, do not add the number! The number of cylinders for this disk is set to 5005files ( There is nothing wrong with that, but this is larger than 1024, and could cause problems with in certain setups: 1) software that runs at boot time (e.g., old versions of LILO) 2) booting and partitioning software from other OSs (e.g., DOS FDISK, OS)/2 FDISK) Command (m for help): <== Wait for your input!
After entering m, you will see these command introductions below
Command (m for help): m <== After entering m, you will see these command introductions below Command action a <== Toggle a bootable flag b <== Edit bsd disklabel c <== Toggle the dos compatibility flag d <== Delete a partition <== Delete a partition l <== List known partition types m <== Print this menu n <== Add a new partition <== Add a new partition o <== Create a new empty DOS partition table p <== Print the partition table <== Display the partition table on the screen q <== Quit without saving changes <== Do not save and leave the fdisk program 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 <== Write the actions to the partition table x <== Extra functionality (for experts only)
Press q when leaving fdisk, then all actions will not take effect! Conversely, pressing w means that the actions will take effect.
Command (m for help): p <== Here you can output the current status of the disk Disk /dev/hdc: 41files (1 GB, 41174138880 bytes <== Name and capacity of this disk 255 heads, 63 sectors/track, 5005 cylinders <== Size of heads, sectors, and cylinders Units = cylinders of 16065 * 512 = 8225280 bytes <== Size of each cylinder Device Boot Start End Blocks Id System /dev/hdc1 * 1 13 104391 83 Linux /dev/hdc2 14 1288 10241437+ 83 Linux /dev/hdc3 1289 1925 5116702+ 83 Linux /dev/hdc4 1926 5005 24740100 5 Extended /dev/hdc5 1926 2052 1020096 82 Linux swap / Solaris # Device file name Boot Yes Start cylinder End cylinder 1K size capacity system inside the disk partition slot Command (m for help): q
Do you want to exit without saving? Press q to do so! Don't press w randomly!
Use p to list the partition table information of the current disk, the upper part of which shows the overall status of the disk.
After the disk partitioning is completed, it is natural to carry out the formatting of the file system, and the command for formatting is very simple, using the mkfs (make filesystem) command.
Syntax:
mkfs [-t File system format] Device file name
Options and Parameters:
-t : Can accept file system format, such as ext3, ext2, vfat, etc. (will take effect if the system supports it)
View the file formats supported by mkfs
[root@www ~]# mkfs[tab][tab] mkfs == mkfs.cramfs mkfs.ext2 mkfs.ext3 mkfs.msdos mkfs.vfat
Press two [tab], and you will find the file formats supported by mkfs as shown above.
Format the partition /dev/hdc6(Can specify your own partition) formatted as ext3 Filesystem:
[root@www ~]# mkfs -t ext3 /dev/hdc6 mke2fs 1files (39 (29-May-2006) Filesystem label= == here refers to the name (label) of the partition slot OS type: Linux Block size=4096 (log=2) == block size configuration 4K Fragment size=4096 (log=2) 251392 inodes, 502023 blocks == inode determined by this configuration/block quantity 25101 blocks (5(0.00%) reserved for the super user First data block=0 Maximum filesystem blocks=515899392 16 block groups 32768 blocks per group, 32768 fragments per group 15712 inodes per group Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912 Writing inode tables: done Creating journal (8192 blocks): done == having log records Writing superblocks and filesystem accounting information: done This filesystem will be automatically checked every 34 mounts or 180 days, whichever comes first. Use tune2fs -c or -i to override. # This creates the Ext we need3 File system! Simple and clear!
fsck (file system check) is used to check and maintain inconsistent file systems.
If the system powers off or the disk has a problem, you can use the fsck command to check the file system.
Syntax:
fsck [-t File system] [-ACay] Device name
Options and Parameters:
-t : Given the type of file system, if in /etc/fstab is already defined or the kernel itself supports it, no need to add this parameter
-s : Execute fsck instructions sequentially to check one by one
-A : For/etc/Check all partitions listed in fstab
-C : Display the complete check progress
-d : Print out e2fsck debug results
-p : At the same time -A When the condition is met, multiple fsck checks are executed together
-R : At the same time -A When condition is met, omit / Do not check
-V : Detailed display mode
-a : If there are errors in the check, it is automatically repaired
-r : If there are errors in the check, the user decides whether to repair
-y : The option specifies that yes is automatically entered for each file checked, and can be executed # fsck when unsure which are abnormal. -y Check and repair all.
Check the number of file systems supported by the fsck command:
[root@www ~]# fsck[tab][tab] fsck fsck.cramfs fsck.ext2 fsck.ext3 fsck.msdos fsck.vfat
Forced check /dev/hdc6 Partition:
[root@www ~]# fsck -C -f -t ext3 /dev/hdc6 fsck 1files (39 (29-May-2006) e2fsck 1files (39 (29-May-2006) Pass 1Checking inodes, blocks, and sizes Pass 2Checking directory structure Pass 3Checking directory connectivity Pass 4Checking reference counts Pass 5Checking group summary information vbird_logical: 11/251968 vbird_logical:9files (1.-% non 36926/1004046 contiguous),
blocks -If the f option is not added, -f Force check, and the process will be displayed item by item.
Linux uses the mount command for disk mounting and the umount command for unmounting.
Disk mount syntax:
mount [-t File system] [-L Label name] [-o Additional options] [-n] Device file name Mount point
Using the default method, mount the just created /dev/hdc6 Mount to /mnt/hdc6 Above!
[root@www ~]# mkdir /mnt/hdc6 [root@www ~]# mount /dev/hdc6 /mnt/hdc6 [root@www ~]# df Filesystem 1K-blocks Used Available Use% Mounted on .....Omitted in the middle..... /dev/hdc6 1976312 42072 1833836 3% /mnt/hdc6
Disk unmount command umount syntax:
umount [-fn] Device file name or mount point
Options and Parameters:
-f: Force unmount! Available in cases similar to network file system (NFS) being unreadable;
-n: Do not upgrade /etc/Unmount under mtab situation.
Unmount/dev/hdc6
[root@www ~]# umount /dev/hdc6