This article is for Amanda Enterprise (AE)
The device BLOCK_SIZE parameter in Amanda configuration files determines the block size for backup images on the storage media (disk, tape, or cloud). This parameter cannot be changed using the Zmanda Management Console (ZMC) for disk or tape. Media block size may be changed in ZMC when writing to cloud by changing the block size used by the cloud device in the Advanced Options section of the Admin|devices page.
The minimum block size is 32 KB which is the default set by ZMC for backup to disk and tape devices. Optimal device block size for disk or tape is the native block size used by your device, ie. file system or tape drive.
Default device block size for backups written to Amazon S3 is 2 MB (2 mega-bytes). There is no native block size for the Amazon S3 device but a reasonable block size should be selected if changed from the default. A block size that is excessively small should be avoided because this can lead to inefficiencies due to the overhead in starting and finishing each block. Block sizes that are excessively large, 1G for instance, should be carefully considered as Amanda keeps a few blocks in server memory at all times during the operation.
To utilize a block size other than the default 32k block size, the device BLOCK_SIZE property must be set to the desired size:
Note: Please observe that each indentation is 2 spaces and must be carefully observed.