/Etc/fstab file analysis (version 2)

/Etc/fstab file Analysis

 

As mentioned above, the new partition will expire after the system is restarted. To take effect permanently, you need to write it to the/etc/fstab file.

 

I./etc/fstab file format: 6 components

 

Physical partition name/volume label mount point file system default settings check Sequence

UUID = 6e428a.../ext4 defaults 1 1

Label = // ext4 defaults 1/0 0/1/2

/Dev/sda1

 

2. Write partition information to/etc/fstab

/Dev/sdb1/testext4defaults1 [Detection If Data Partition is used] 2 [detection order ratio/back]

In this way, the partition is automatically mounted when the system starts and does not need to be manually mounted.

 

Iii. Marking

E2label/dev/sda1 // query the volume label

E2label/dev/sdb2 Apache // set the volume label

In this case, you can write it to the/etc/fstab file: Change/dev/sdb1 In the first line to label = Apache, which has the same effect [However, it has been proved by experiments that, in centos 6.4, the scalping method is not supported. Remember]

 

4. added the swap Partition Function for swapfile

Scenario: there is no new hard disk, but you still need to increase the space of the SWAp partition...

 

1. mkdir/var/swap

Chmod 700/var/swap // create a directory for storing swap virtual swap space

 

2. dd If =/dev/Zero of =/var/SWAP/file. swp bs = 1024 k count = 10

 

BS [block size] # specify the file block size. UNIX does not support K.

Count # specify the file. SWP file size in BS.

 

Then: dd If =/dev/Zero of =/var/SWAP/file. swp bs = 1024 k count = 10 # specify/var/SWAP/file. the size of the SWP file is 10 MB, and the size of all the file content is 0.

 

[Use this command to create a very large file to test the read/write speed of the disk and test whether the disk is full]

 

3. mkswap/var/SWAP/file. SWP # create a swap space

4. Swapon/var/SWAP/file. SWP # enable the newly created swap space

Swapoff/var/SWAP/file. SWP # disable the swap space]

 

5. Write the swap space to the/etc/swaptab file. The swap space is automatically loaded every time the system starts.

/Var/SWAP/file. SWP swap defaults 0 0

 

Attachment-disk Copy command

Dd If =/dev/SDA of =/dev/SDB realize Disk/dev/SDA and/dev/SDB copying

 

Appendix-free view memory information

Free-M #-M is displayed in MB, and-G is displayed in G.

 

Appendix-two pseudo devices in Linux

/Dev/Zero: input 0 to the file.

/Dev/null File black hole

/Etc/fstab file analysis (version 2)