Active SQL Backup

• 1. Features
• 2. Incremental backup advantages
• 3. Incremental backup pitfalls
• 4. Active SQL Backup and other programs
• 4.1. Active SQL Backup and Mysqldump utility
• 4.2. Active SQL Backup and Mysql utility
• 5. Read program's help file
• 6. FAQ
• 6.1. May I modify Active SQL Backup?
• 6.2. Is Active SQL Backup free of charge?
• 6.3. Can my data go insecure if I perform a backup?
• 6.4. MySQL update logs are useful for this thing...
• 6.5. My hosting provider already does database backup...
• 7. History

1. Features

• Perform *incremental* backup of MySQL database
• Perform full backup of MySQL database
• Replicate database
• Process SQL queries
• Dump database structure
• Suggest database changes needed to process incremental backup
• Send data backed up by email
• Transfer backed up data by FTP to other computer (if Net::FTP is installed)
• Compress backed up data

2. Incremental backup advantages

Consider an internet exam practicing service which must keep a log of all students' exams. If you perform *daily* backups, then in a year full backup files are on average 365 times bigger than incremental backup files and full backup takes 100-365 times longer. When there are much data, backup may take even an hour to complete. Can you afford to shut down your system for an hour every day? Even if you perform *weekly* backups, incremental one will be up to 52 times faster than a full one in a year. And it would take about 1-2 minutes, where full backup would take one hour. Thus with incremental backup you can make backups more frequently, and if the system will crash, the less data you will lose.

There is also another consideration to take into account. If your web site is on a shared server, then a web hosting company policy may not allow a task to consume much system resources. And your program may be simply terminated by an admin if it takes too much. With incremental backup there are usually much less data to save, so it takes less resources.

3. Incremental backup pitfalls

There are several things that you should be aware. Almost all of them are described in the manual.

• You'd better avoid dropping columns from tables, however you *can add* columns.
• There is a problem with the records that were deleted after the backup was made. On restore they again arrive in the table.
• You should not rename backed up files.
• Probably you will need to add a "mark-up" column to the table that you want to back up in increments. Active SQL Backup can do this for you, see "zmdb.pl -a".
• You need to write some lines of code to describe the tables you want to be backed up incrementally. Active SQL Backup can do this for you, see "zmdb.pl -a".
• In some cases you may need to change the SQL code of your application. This is needed when you use short SQL syntax with implicit field names such as "select * from..." with tables that need modification.

4. Active SQL Backup and other programs

4.1. Active SQL Backup and Mysqldump utility

Active SQL Backup is focused on incremental backup. Mysqldump is a very good utility, but primarily aimed at full database backup. Therefore incremental backup can not be done using *only* Mysqldump, merely because storage of "mark-up" values is needed. Also certain things like "incremental backup with update" can't be done using Mysqldump, because index duplication on insert may occur. And on some systems Mysqldump might be missing. Active SQL Backup is not a direct replacement of Mysqldump, because it lacks certain features of Mysqldump, but can do full backups as Mysqldump.

4.2. Active SQL Backup and Mysql utility

Mysql is a client utility that can connect to MySQL database and perform SQL queries. Active SQL Backup can also perform SQL queries by itself, but lacks many features of mysql utility, such as interactive mode. Mysql utility might be missing on some computers. If it is available, Active SQL Backup uses mysql utility for restore.

5. Read program's help file

Help file, which is included in the distribution, can give you the detailed information on how the program works, about the format of files, setup procedure and other details. We suggest that you browse through it.

Have a look at help file.

6. FAQ

6.1. May I modify Active SQL Backup?

Just for your own internal use. You may not redistribute or sell modified copies without our written permission.

6.2. Is Active SQL Backup free of charge?

Yes.

6.3. Can my data go insecure if I perform a backup?

This problem is not related directly to Active SQL Backup, however we take all precautions to make it safe. All dump files are allowed to read or write only by your userid, i.e. are chmod'ed 0600. Backup folder is chmod'ed 0700 also. You should chmod 0700 zmdb.pl script and 0600 all other Active SQL Backup files.

6.4. MySQL update logs are useful for this thing...

Yes. But most web sites that use MySQL are on shared web servers. For security reasons users on a shared server are not allowed to read MySQL update logs, so these logs are useless for them. :(

So if you are on a shared server (and this is usually the case unless you pay some hundreds dollars a month for a dedicated server), you need Active SQL Backup.

6.5. My hosting provider already does database backup...

This utility is useful for you anyway. :)

Providers usually do backups at the file level, copying MySQL files directly. And if something is wrong with the table files, then wrong files are backed up :( Incremental backup is free from this problem.

Even if they do backups, providers usually perform it 1-2 times a week. With Active SQL Backup you can do it more often, keeping mission-critical data safe.

The other reason is that you can transfer data to other SQL server or to other MySQL server. The utility has FTP and email capabilities for this purpose.

7. History

Please read complete changes history in help file.