Version compatibility

Compatibility

Amanda has used several on-the-wire protocols to communicate between the server and backup clients, and not all of them have been compatible.

• Versions of Amanda prior to about 2.3 used a different protocol which is not compatible. 2.3 is very old so this is not of general interest.

• The Amanda 2.4 series all use the same protocol. This protocol has support for extensibility. Generally upgrading clients or servers along the 2.4 branch does not cause difficulty.

• Amanda 2.5.0 uses the same protocol as 2.4. One can use a 2.5.0 server with 2.4 clients and a 2.4 server with 2.5.0 clients.

• Kerberos4 authentication in 2.5 is compatible with 2.4. In 2.5, kerberos4 encryption is broken, at least for the server.

• Amanda 2.5.1 introduced a new recover protocol. Backup communication works with any combination of versions, but 2.5.1's amrecover cannot communicate with an older server. Use oldamrecover on 2.5.1 and higher clients when communicating with an older server.

• Amanda 2.6.0 is completely compatible with 2.5.1.

To restore a dump created with the tapesplit_size option using amrecover, you need a 2.5 server + 2.5 client. (Extracting that backup using only shell, mt and dd is also possible.)

Upgrading

The recommended course for upgrades is to upgrade the server to 2.5 first, and test backups and restores before upgrading clients. Both upgrades should be seamless, although you may wish to adjust your server configuration to account for new features like tape spanning.