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volume efficiency start

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Starts efficiency operation on a volume

Availability: This command is available to cluster and Vserver administrators at the admin privilege level.

Description

Use the volume efficiency start command to start an efficiency operation. The volume must be online and have efficiency enabled. If there is an efficiency operation already active on the volume, this command fails.

When the volume efficiency start command is issued, a checkpoint is created at the end of each stage or sub-stage, or on an hourly basis in the gathering phase. If at any point the volume efficiency start operation is stopped, the system can restart the efficiency operation from the execution state saved in the checkpoint. The delete-checkpoint parameter can be used to delete the existing checkpoint and restart a fresh efficiency operation. The checkpoint corresponding to gathering has a validity period of 24 hours. If the user knows that significant changes have not been made on the volume, then such a gatherer checkpoint whose validity has expired can be used with the help of the use-checkpoint parameter. There is no time restriction for checkpoints of other stages.

When the volume is configured to use the inline-only efficiency policy, the system will stop monitoring changes to the data for the purpose of running background efficiency operations. The background deduplication operations will be disabled. The user can still execute compression specific efficiency operation with -scan-old-data and -compression parameters to compress the existing data on the volume.

Parameters

-vserver <vserver name> - Vserver Name

Specifies the Vserver on which the volume is located.

{ -volume <volume name> - Volume Name

Specifies the name of the volume.

| -path </vol/volume> - Volume Path }

Specifies the complete path of the volume.

[-s, -scan-old-data <true>] - Scan Old Data

This option scans the file system and processes all existing data. It prompts for user confirmation before proceeding. Use the force option to suppress this confirmation.

{ [-p, -use-checkpoint <true>] - Use Checkpoint (if scanning old data)

Use the checkpoint when scanning existing data. Valid only if scan-old-data parameter is true.

| [-d, -delete-checkpoint <true>] - Delete Checkpoint }

Deletes the existing checkpoint and restarts a new volume efficiency start operation.

[-qos-policy <sis_qos>] - QoS Policy

Specifies the qos-policy, which indicates how the efficiency operations are throttled. This option can be configured to be background or best-effort . Default value is best-effort . If background is specified, the efficiency operations are run with minimum or no impact on the data serving client operations. If best-effort is specified, the efficiency operations might have some impact on the data serving client operations.

[-C, -compression <true>] - Start Compression (if scanning old data) (privilege: advanced)

Compresses existing data. Deduplication is not run unless the dedupe option is also specified. Valid only if scan-old-data parameter is true.

[-D, -dedupe <true>] - Start Deduplication (if scanning old data) (privilege: advanced)

Deduplicates existing data on disk. Similarly, compression is not run unless the compression option is also specified. Valid only if scan-old-data parameter is true.

[-P, -compaction <true>] - Start Compaction (if scanning old data) (privilege: advanced)

Compacts existing data on disk. Valid only if scan-old-data parameter is true.

[-m, -build-metadata <true>] - Build metadata without sharing(if scanning old data)

Builds deduplication metadata by scanning the entire file system. You will not achieve any space savings with this option. Once the metadata is built, existing data can be shared with newly written data on subsequent deduplication runs.

[-o, -scan-all <true>] - Scan all the data without shared block optimization(if scanning old data)

Scans the entire file system and processes the shared blocks also. You may be able to achieve additional space savings using this option. Where as, by default the option –scan-old-data saves some time by skipping the shared blocks.

[-a, -shared-blocks <true>] - Compress Shared Blocks (if scanning old data) (privilege: advanced)

Compresses the Compression Groups that have shared blocks created by deduplication or cloning data. Valid only if scan-old-data parameter is true.

[-b, -snapshot-blocks <true>] - Compress Blocks In Snapshots (if scanning old data) (privilege: advanced)

Compresses data blocks locked in a Snapshot copy. Valid only if scan-old-data parameter is true.

[-q, -queue <true>] - Operation Should Be Queued

Queues an efficiency operation. It will be queued only if an operation is already in progress. Valid only if scan-old-data is false.

[-f, -force <true>] - Force Operation

Suppresses all confirmation messages.

[-z, -skip-zero-replacement <true>] - Skip Zero block detection and replacement (privilege: advanced)

Skip the zero block detection and replacement during the gatherer scan. Valid only if scan-old-data parameter is true.

Examples

The following examples start efficiency on a volume:

cluster1::> volume efficiency start -volume vol1 -vserver vs1
cluster1::> volume efficiency start -scan-old-data -volume vol1 -vserver vs1
cluster1::> volume efficiency start -volume vol1 -vserver vs1 -queue -delete-checkpoint