dd is a very handy tool and there are some more practical things we can do. For example if we want to dump a 3TB drive and want to preserve it and only 200GB are being used on the 3TB we can save a lot of space with gzip.
Backing Stuff up with dd
How to Use dd to backup a raw hard drive and tar gzip at once
Change /dev/sda to the drive you want to backup
The solution is simple but strange, if you copy your /var/lib/mysql directory to another server and think it will work, be sure to check if you have /var/log/mysql and binary log files. If you do, the server will not work and will give you errors like below and crash without the proper log files.
UPDATE user SET password=password("newpass") WHERE user='root';
ERROR 2013 (HY000): Lost connection to MySQL server durin........
don't delete /var/lib/mysql/ib_logfile0 or ibdata1 or mysql won't restart
I didn't realize they were internal and not part of replication like the relay files!
/usr/libexec/mysqld: ready for connections.
Version: '4.1.22-log' socket: '/var/lib/mysql/mysql.sock' port: 3306 Source distribution
110127 16:31:00 [Note] /usr/libexec/mysqld: Normal shutdown
110127 16:31:00 InnoDB: Starting shutdown...........
Adding IP address(es): 192.168.5.8 192.168.5.9
Setting CPU units: 1000
Error: undump failed: Invalid argument
Error: iptables-restore exited with 2
Error: Most probably some iptables modules are not loaded
Error: rst_restore_net: -22
Container start failed
Stopping container ...
Container was stopped
Container is unmounted
Error: Failed to undump VE
vzquota : (erro........
vzmigrate --online dest-host VEIDNO
vzmigrate --oneline 192.168.1.55 101
One option I would recommend is "--keep-dst", that way if the migration is interrupted you can still bring the VPS back up on the original host. After the migration is successful you can manually destroy it.
OpenVZ has a good writeup on this including Checkpointing and Restoring etc:........
It is desirable to strip the leading slashes when taring / because you wouldn't want to overwrite your entire system when extracting some files to check.
But if you are restoring / from the tar you want the leading slashes added again. Here's how to do it:
Either one above will do the same thing.........
Backing MySQL Databases
Backing Up/Dumping All Mysql Databases To A Single File
mysqldump --all-databases -u admin -p > allmysqldatabases.sql
The "-all-databases" clause is pretty obvious isn't it? It means that it will backup all databases.
The "-u admin" means login using the user "admin", if you h........