Configuring DWS Snapshot Parameters
You can configure the parameters for creating and restoring a snapshot.
Notes and Constraints
- This feature applies only to clusters of version 8.2.0 or later. (For clusters of versions earlier than 8.2.0, only some parameters can be configured.)
- The parameters take effect on all the snapshot creation and restoration tasks.
- The thread-count configuration is available in cluster 9.1.0.210 and later versions. When Roach initiates a multi-threaded backup of cold and hot tables, and V3 tables, the default number of concurrent threads is set to twice the number of CPU cores.
- For clusters using Roach 1.5.3 or later, snapshot and restoration parameters are included in the cluster parameters. You can click Configure Parameters and modify backup and restoration parameters of a cluster. (To upgrade the Roach plug-in, contact technical support engineers.)
Procedure
- Log in to the DWS console.
- In the navigation pane on the left, choose Cluster > Cluster List.
- In the cluster list, click the name of the target cluster. The Cluster Information page is displayed.
- In the navigation pane, click Snapshots. Click Parameter Configurations. All the configurable parameters of the current cluster will be displayed.
- Configure parameters as required. For details, see Table 1.
- Click Save.
Snapshot Parameters
| Parameter | Type | Description | Default Value |
|---|---|---|---|
| parallel-process | Backup parameter | Number of concurrent processes on each node during Roach backup. This parameter can be configured for clusters earlier than 8.2.0. | The value is the number of DNs on the current node. |
| compression-type | Backup parameter | Compression algorithm type. This parameter is supported by clusters earlier than 8.2.0.
| LZ4 |
| compression-level | Backup parameter | Compression level. The value range is 0 to 9. This parameter is supported by clusters earlier than 8.2.0.
| 6 |
| buffer-size | Backup parameter | Buffer size of the Roach upload media, in MB. The value range is 256 to 16384. | 256 |
| buffer-block-size | Backup parameter | Data block size of the data file to be read by Roach, in bytes. The value range is 5242880 to 268435456. | 67108864 |
| cpu-cores | Backup parameter | Number of CPU cores that can be used when Roach starts multiple threads concurrently | 1/2 of the total number of logical CPU cores on the node |
| master-timeout | Backup parameter | Timeout period for the communication between the Roach master and agent nodes, in seconds. The value range is 600 to 3600. | 3600 |
| max-backup-io-speed | Backup parameter | I/O flow control during Roach backup, in MB/s. The value range is 0 to 2048. The value must be greater than the value of buffer-block-size. The value 0 indicates no limit. | 0 |
| backup-mode | Backup parameter | Full backup mode.
| 0 |
| cbm-parse-mode | Backup parameter | Incremental backup mode.
| 0 |
| thread-count | Backup parameter | Number of concurrent threads used when Roach starts multi-thread backup of cold and hot tables and V3 tables. A high parameter value may block access to OBS. This parameter is supported only by clusters of version 9.1.0.210 or later. | 4 |
| dump-options | Backup parameter | Backup options supported during fine-grained backup. DWS supports permission and comment backup. This parameter is supported only by clusters of version 9.1.0 or later.
| Do not back up permissions and comments. |
| logging-level | Backup parameter | Backup log level
| FATAL, ERROR, WARNING, INFO, DEBUG, or DEBUG2 |
| parallel-process | Restoration parameter | Number of concurrent processes on each node during Roach backup. By default, the value is the number of primary DNs on the current node plus 1. | 1 |
| cpu-cores | Restoration parameter | Number of CPU cores that can be used when Roach starts multiple threads concurrently | Half of the number of CPU cores |
| logging-level | Restoration parameter | Log levels:
| INFO |
| restore-by-insert | Restoration parameter | Fine-grained restoration mode. If this parameter is specified for a fine-grained restoration, the INSERT statement will be used to restore the target table. Otherwise, the ALTER statement will be used. | ALTER |
| thread-count | Restoration parameter | Number of concurrent threads used when Roach starts multi-thread restoration of cold and hot tables and V3 tables. A high parameter value may block access to OBS. This parameter is supported only by clusters of version 9.1.0.210 or later. | 4 |
| dump-options | Restoration parameter | Restoration options supported during fine-grained restoration. DWS supports permission and comment restoration. This feature relies on the configuration of the snapshot dump-options backup parameter. This parameter is supported only by clusters of version 9.1.0 or later.
| Do not restore permissions and comments. |
