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.

Procedure

Log in to the DWS console.
Choose Dedicated Clusters > Clusters in the navigation pane.
In the cluster list, click the name of the target cluster. The Cluster Information page is displayed.
Click the Snapshots tab page and click Configure Parameters. All the configurable parameters of the current cluster will be displayed.
Configure parameters as required. For details, see Table 1.
Click Save.

Snapshot Parameters

**Table 1** Snapshot parameters
Parameter	Type	Description	Default Value
parallel-process	Backup parameter	Number of concurrent processes on each node during Roach backup. NOTE: 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 zlib LZ4 NOTE: This parameter can be configured for clusters earlier than 8.2.0.	LZ4
compression-level	Backup parameter	Compression level. The value range is 0 to 9. 0: fast backup and no compression 9: slow backup and maximum compression NOTE: This parameter can be configured for clusters earlier than 8.2.0.	6
buffer-size	Backup parameter	Buffer size of the Roach upload media. The value range is 256 to 16,384, in MB.	256
buffer-block-size	Backup parameter	Data block size of the data file to be read by Roach. The value range is 5,242,880 to 268,435,456, in bytes.	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. The value range is 600 to 3600, in seconds.	3600
max-backup-io-speed	Backup parameter	I/O flow control during Roach backup. The value range is 0 to 2048, in MB/s. 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: phase-1 backup 1: phase-2 backup	0
cbm-parse-mode	Backup parameter	Incremental backup mode 0: one-time CBM scan (high memory usage and high performance) 1: multiple CBM scans (stable memory usage and low performance)	0
thread-count	Backup parameter	Number of concurrent threads used when Roach starts multi-thread backup of cold and hot tables and V3 tables. The maximum value is 16 times the number of CPU cores. NOTE: This parameter is supported only by clusters of version 9.1.0.210 or later.	The default value is twice the number of CPU cores.
dump-options	Backup parameter	Backup options supported during fine-grained backup. DWS supports permission and comment backup. Permission: enable_handle_acl Comment: enable_handle_comment NOTE: This parameter is supported only by clusters of version 9.1.0 or later.	Do not back up permissions and comments.
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	The default value is 1/2 of the number of CPU cores.
logging-level	Restoration parameter	Log level FATAL: Unrecoverable faults that cause the system suspension. This is the most severe level. ERROR: Major errors. WARNING: Exceptions. In this case, the system may continue to process tasks. INFO: Notes. DEBUG: Debugging details. DEBUG2: Detailed debugging information, which is generally not displayed. This is the least severe level.	INFO
thread-count	Restoration parameter	Number of concurrent threads used when Roach starts multi-thread restoration of cold and hot tables and V3 tables. The maximum value is 16 times the number of CPU cores. NOTE: This parameter is supported only by clusters of version 9.1.0.210 or later.	The default value is twice the number of CPU cores.