Replication bandwidth can be consumed by several features. VMS features an automatic priority system that distributes replication bandwidth among the various types of replications streams. There are also some controls you can use to manually adjust priorities should you find that replication jobs are not meeting their RPOs.
Replication bandwidth can be consumed by the following features:
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A protected path replication stream doing an initial sync.
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A global snapshot being cloned on a remote peer.
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A protected path replication stream transferring the delta between two snapshots. This type of job is expected to meet an RPO.
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A request to fetch data or metadata from a remote cluster from a global snapshot clone.
VMS provides commands for viewing the replication streams in progress and their current priorities, and for manually adjusting priority scores.
To view all replication streams, run the replicationstream list command.
For example:
vcli: admin> replicationstream list +------+-----------------------------+-------------+--------+-----------------------------------------------------------------------------------+-------------------+-----------------+--------------------+----------------+-----------------+--------------------------+ | ID | Name | Role | State | Source-dir | Protected-path-id | Bandwidth(MB/s) | Remote-tenant-name | Priority-score | Priority-number | Is-manual-priority-score | +------+-----------------------------+-------------+--------+-----------------------------------------------------------------------------------+-------------------+-----------------+--------------------+----------------+-----------------+--------------------------+ | 5479 | S3 replication path 448 | Destination | Active | /s3_replication/sources/a0575298-cb2b-5421-9968-597f6bd74835/9223372035164920616 | 5478 | None | mgmt | 0.0 | 3 | False | | 5475 | S3 replication path 5475 | Source | Active | /s3_replication/targets/31236bca-333a-430d-974b-bf6acca0fe3b | 5474 | 0.000 | mgmt | 0.731 | 5 | False | | 5476 | Rep path 1 | Destination | Active | /rep/path/1 | 5477 | None | mgmt | 0.0 | 1 | False | | 5474 | Rep path 2 | Source | Active | /rep/path/2 | 5473 | 0.000 | mgmt | 0.681 | 4 | False | | 5487 | repli-kate | Destination | Active | /a | 5486 | None | replica | 0.0 | 2 | False | +------+-----------------------------+-------------+--------+-----------------------------------------------------------------------------------+-------------------+-----------------+--------------------+----------------+-----------------+--------------------------
This command shows you the following information about each stream's current priority scoring:
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Priority-score. This score is set automatically and can optionally be set manually. The lower the value, the higher the priority the stream has. The value can be negative or positive. -
Priority-number. This is a positive integer value reflecting the stream's position in order of score. The stream with the lowest priority-score has priority number 1, which means it has highest priority.
To view details of a specific replication stream, run the replicationstream show command.
For example:
vcli: admin> replicationstream show --id 5487 +--------------------------+-------------+ | ID | 5487 | | Name | rep-lica | | Role | Destination | | State | Active | | Source-dir | /a | | Protected-path-id | 5486 | | Bandwidth(MB/s) | None | | Remote-tenant-name | rep-lica | | Priority-score | 0.0 | | Priority-number | 2 | | Is-manual-priority-score | False | +--------------------------+-------------+
To change the priority of a stream, run the replicationstream modify command with the --priority-score parameter. To restore automatic priority scoring for the stream, run the command again with the --auto-calculate-priority-score parameter.
Set a smaller score to prioritize a stream and a larger value to de-prioritize a stream. Since automatic scores are usually between 0 and 1, it can be effective to set a large negative value when you need to prioritize a stream.
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