Memory View command
free use of memory and can be viewed free swap usage
For a more user-friendly display can use parameters -mgt the results by (MGT) to display the default kb
top top command to display the dynamic memory usage and swap
Disk View command
fdisk -l can view disk and partition cases
df -h can also view the disk mount case
du file to view the file size of the file can be used -mgt
du view the file size of the actual space ls information see the file size in the inode
dd if = / dev / zero bs = 4M count = 10 seek = 20 of = bfile copy of bytes from if to
bs as blocksize count is the number of bs seek to seek Where to start from bfile used to create the file empty
Filesystem common file system ext4 (manjaro) xfs (centos)here is ext4 record basic information:
Superblock beginning of the disk portion of the recording disk partition information will be more important superblock copy
inode i-node other than the file name to save the file information (file name stored in the inode parent directory) can be used to view files ls -i inode numbers
datablock save the contents of the file pointer to the inode will datablock inode is a vivid metaphor for the datablock locomotive train cars
Some operations inode changes:
cp Copy a file creates two files inode number of different
mv renaming within the same directory inode number change depending on when not operating within the same directory is not in the same partition may be operating in the same block partition quickly just rename it no longer will need to copy the same partition
vim before and after the file using vim inode numbers different in vim when .swp will produce a file in the directory to save the original file will quit vim
rm disconnect the link between the file name and file inode so no matter how much always delete files quickly
ln increase file when the link between the name and the inode use only ln can not cross operation is called common connection
ln -s can cross operation is called a symbolic link will generate a new inode 777 permissions for the linked file permission changes will affect without affecting the linked file is a symbolic link file
facl ask file access control list records file permissions information
getfacl file get file information file permissions
setfacl -mu: user1: rw file set permissions on the file to user1 RW -m impart appropriate permissions -x revoke permissions u: represents a respective set user rights g: setting group permissions
Configuration file / etc / fstab /
/ Dev / sda / mnt / sdc1 ext4 (file type) Defaults (read default settings) 0 (whether or not backup) 0 (if POST)
Partitions and mount
fdisk / dev / sda to partition the disk sda
mkfs.ext4 / dev / sda when the disk is formatted as ext4 sda type (format to another format in the mkfs.ext4 replace other formats ext4
mount -t ext4 / dev / sda / mnt / sdc1 the sda mount sdc1 -t specified file system types
The above steps are only a temporary partition (records stored in the memory) is still valid if you want to restart the system after the need to modify the configuration file / etc / fstab
parted on T unit level disk operations
User disk quotas to restrict users to use the system disk resources
Use when mounting mount -o uqota, gqota support disk quotas
Then use xfs_quota command operations inode number b i restriction limits the number of datablock
Swap supplement when using an existing swap partition is not enough you can use Disk Expansion can also use the file expansion
mkswap with a new hard drive to expand and then format the mount
swapon open swap swapoff closed swap
File expansion can create a file using the dd command and then mount format
RAID disk entire column
RAID0 Striping striped two disk mode operation for increased throughput
RAID1 the mirroring in the mirror mode is generally used to reduce the capacity of the backup and high reliability
RAID5 parity three disks
RAID10 combines RAID0 and RAID1 method requires four disk
Software RAID mdadm command
Logical to physical volumes in a volume group and a logical volume may be redistributed as desired use pvcreate vgcreate lvcreate pvs lvs commands