15th. Backup and Recovery "complete book"

1. Backup Overview

(1) data that the Linux system needs to back up

①/root/Directory

②/home/Directory

③/var/spool/mail/Directory

④/etc/Directory

⑤ Other Directories

(2) Data for installation Services

①apache data to be backed up: Configuration files, Web page home directories, log files, etc.

②mysql the data that needs to be backed up: The source package installs the MYSQL:/USR/LOCAL/MYSQL/DATA/;RPM package installed mysql:/var/lib/mysql/

(3) Backup policy

　　① Full backup: full backup means all the data that needs to be backed up, and of course a full backup can back up the entire disk, the entire partition, or a specific directory.

② Incremental Backup:　　 make a full backup for the 1th time , and then just back up the data that has been added since the last backup . This only backs up new data at a time, is faster and saves space , but recovery is cumbersome and needs to be restored in the same order as the backup, and how many incremental backups will have to be recovered.

③ differential Backup:　　 The 1th full backup , the 2nd backup of the new data after the full backup , the 3rd backup 2nd backup and later data, 4th backup will be the 2nd backup, 3rd Backup and 3rd after the new data back up, and so on . that is, each backup is compared to a full backup, as long as the new data is backed up after a full backup . The advantage is that the recovery is easier, the more occupied space is relatively large.

2. Dump and restore commands

2.1 Dump Command :

(1) Install the dump command

grep Dump  // Query the installation package where the dump command is installed #yum Install Dump  // Install dump command

(2) command format:#dump [options] After the backup file name of the original file or directory

tr>

options	Description
-level	10 backup levels (0-9), where 0 indicates a 1th full backup, 1 represents an incremental 2nd time backup, 2 represents an incremental 3rd backup, and so on, Span style= "COLOR: #0000ff" > supports up to 9 times .
-f file name	Specify file name after backup
-u	After the successful backup, Log the backup time in the/etc/dumpdates file
-v	Show more output information during backup
-j	Call Bzlib Library compressed file, in fact, is to compress the backup file into. bz2 format
-w	Query partition backup level and backup time (view only the backup status of the partition)

(3) Application examples

　　① Backup/boot partition:(partitions can be fully backed up and incremental)

#dump -0uj-f/root/boot.bak.bz2/boot/  // 1th Full backup #cat /etc/dumpdates   // View backup Time Files # CP install. log/boot/   Copy log file to/-1uj-f/root/boot.bak1.bz2/boot/   Incremental backup/-W Query partition backup time and backup level

　　② Backup directory ( directory can only be fully backed up and cannot be incrementally backed up )

#dump -0j–f/root/ect.dump.bz2/etc/Full Backup/etc directory, you can only use 0 levels for full backups, and no incremental backups are supported.

2.2 Restore Command

(1) command format:#restore [mode options] [options]

Mode options	Description
-C	Compare backup data with actual data changes
-I.	Enter interactive mode and manually select the files to be recovered
-T	View mode for viewing what data is in the backup file
-R	Restore Mode for data restore
Note	The restore mode cannot be mixed.
Options	Description
-F	Specify file name for backup files

(2) Application examples

　　① view mode:#restore-T-F boot.bak.bz2

　　② Restore Mode

#mkdir  boot.test#cd boot.test///    Restore the backed-up data to the Boot.test directory  -r-f/root /BOOT.BAK.BZ2  // restore data from a full backup   // Restore an incremental backup

15th. Backup and Recovery "complete book"