Recommended Configurations
This section provides recommended configurations for Background and Fast modes.
The HDFS Balancer can run in either Background or Fast modes.
- Background Mode
HDFS Balancer runs as a background process. The cluster serves other jobs and applications at the same time.
- Fast Mode
HDFS Balancer runs at maximum (fast) speed.
Table 5.2. Datanode Configuration Properties
| Property | Default | Background Mode | Fast Mode |
|---|---|---|---|
| dfs.datanode.balance.max.concurrent.moves | 5 | 4 x (# of disks) | 4 x (# of disks) |
| dfs.datanode.balance.bandwidthPerSec | 1048576 (1 MB) | use default | 10737418240 (10 GB) |
Table 5.3. Balancer Configuration Properties
| Property | Default | Background Mode | Fast Mode |
|---|---|---|---|
| dfs.datanode.balance.max.concurrent.moves | 5 | # of disks | 4 x (# of disks) |
| dfs.balancer.moverThreads | 1000 | use default | 20,000 |
| dfs.balancer.max-size-to-move | 10737418240 (10 GB) | 1073741824 (1GB) | 107374182400 (100 GB) |
| dfs.balancer.getBlocks.min-block-size | 10485760 (10 MB) | use default | 104857600 (100 MB) |