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  1. Home
  2. NetBackup™ for Cloud Object Store Administrator's Guide
  3. Managing Cloud object store assets
  4. Configuring advanced dynamic multi-streaming parameters
NetBackup™ for Cloud Object Store Administrator's Guide

Configuring advanced dynamic multi-streaming parameters

You can configure these optional parameters in the backup host.

Table: Advanced parameters for backup host

Parameter

Default/ Configuration

Description

COSP_LIST_API_
MAX_OBJECTS

Default:

5000 for Azure backups and 1000 for AWS/S3 backups.

Configuration:

  • 100 - 5000 for Azure

  • 100 - 1000 for S3/AWS

During object listing, this value is used as the batch size in the ListObject API. Reducing this value may slow down the overall backup process. It is recommended to set it according to your cloud provider's specifications or recommendations.

COSP_DOWNLOAD_
OBJECT_PART_
SIZE_IN_MB

Default: 16

Configuration: 1 - 512

Represents the size of each chunk or part used when downloading large objects in multiple chunks. If the cloud is fast and capable of handling larger chunks efficiently, increasing this value may improve the overall backup speed.

COSP_TOTAL_
OBJECT_DOWNLOAD_
WORKERS

Default: 160

Configuration: 10 - 1000

This parameter determines the number of parallel tasks used to download objects from a specified bucket. If the cloud is slow, increasing this value can cause issues such as request failures or retries. However, if the cloud is fast, increasing this value can speed up the backup process. It's also important to note that increasing the number of workers consumes more CPU resources. Since this value applies to each backup job, it's crucial to configure it carefully, especially when running multiple parallel jobs.

COSP_STREAM_
CHANNEL_BUFFER_
SIZE

Default: 100

Configuration: 100 - 5000

This parameter restricts the total buffer size/number of objects to keep in the cache for processing after listing. If multiple streams are running, then this is the buffer/cache size of each stream.

COSP_DB_INSERT
_BATCH_SIZE

Default: 500

Configuration: 500 - 5000

Represents the number of downloaded objects that are sent to bpbkar for final processing. Increasing this value to an optimistic number, such as 1000, can boost the overall backup speed, provided the staging location has sufficient space to handle the batch size. However, if the staging location lacks enough space, increasing this value may slow down the backup process.

COSP_STAGING_
LOC_WATER_MARK_
IN_PERCENTAGE

Default: 80

Configuration: 30 - 80

This parameter restricts the usages of the staging location. It accepts the value in percentage. The default value is 80. The range is 30 to 80. For example,

COSP_STAGING_LOC_
WATER_MARK_IN
_PERCENTAGE= 70
COSP_SPACE_
MANAGEMENT_TIMEOUT
_IN_MIN

Default: 5

Configuration: 5 - 60

The time to wait before starting a backup, if the required space is not available on the temporary staging location. The value is in minutes. Default value = 10. The range is 5 to 60 (minutes). For example:

COSP_SPACE_
MANAGEMENT_TIMEOUT
_IN_MIN = 20

You can configure this optional parameter in the primary server.

Table:

Parameter

Default/ Configuration

Description

DYNAMIC_STREAMING
_START_CHILD_BACKUP
_JOBS_TIMEOUT 

Default: 600 (Seconds)

Configuration: 600 - 3600 (Seconds)

This timeout value determines how long each parent job waits to start all its child jobs, when multiple jobs are triggered with multiple streams. If the timeout is reached, the job fails with a crawler timeout error. We recommend setting this value as high as possible if multiple backups are running. Note that this setting takes effect only before running a backup job.

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