Avamar: How to configure backup modes

Avamar/Isilon Backup Mode Instructions

To run backups using Avamar/Isilon, follow these steps:

• Choose between two backup modes: Timestamp and snapshot.
• Timestamp mode runs a timestamp-based backup, also known as token-based backup.
• Snapshot mode runs a snapshot-based backup, also known as fast incremental backup.

To configure a token-based backup:

• Set the NDMP parameter --enable-isilon-fast-incrementals=false in avndmp.cmd or in the dataset under advanced options.
• The default setting is --enable-isilon-fast-incrementals=true, and this is automatically configured.

To configure faster-incremental backup:

• Ensure the NDMP parameter --enable-isilon-fast-incrementals=false is NOT set (enabled is the default setting).
• Add the parameter BACKUP_OPTIONS 0x00000004 on the Isilon side to keep previous snapshots.

To switch from faster-incremental backup to token-based backup:

• Set the NDMP parameter --enable-isilon-fast-incrementals=false.

To switch from token-based backup to fast-incremental backup:

• Run a new level 0 backup.
• The snapshots are compared to determine what must be backed up:

# Example of setting NDMP parameter
$ cat avndmp.cmd 
--enable-isilon-fast-incrementals=false

NOTE: OneFS preserves the previous three snapshots.

Token-Based Backup: With a token-based backup, Direct Memory Access (DMA) passes a timestamp value in an NDMP environment variable, BASE_DATE to the backup server.
The backup server creates a snapshot of all files changed after the timestamp. These files are sent to Avamar to back up. Timestamp zero (0) forces a full backup. DMA in this case would be the Avamar NDMP Accelerator.

Faster-Incremental backup: This is the default for an Avamar backup, called isilon-fast-incrementals.
To disable faster-incremental backup and revert to token-based, set up the NDMP parameter below in the avndmp.cmd or in the dataset under advanced options:

--enable-isilon-fast-incrementals=false

This is the faster backup method if the data change rate is smaller than 3%.

If no snapshot is found, the backup defaults to Token Based Backup and runs a level 0 backup. 
This snapshot is preserved and then used as the initial level 0 backup for the faster-incremental backup.