PowerScale OneFS 9.3.0.0 CLI Administration Guide

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Run the defragmenter

The ShadowStoreDelete job runs the defragmenter. There is also a CLI command that runs the defragmenter.

The following table describes the two methods for running defragmentation.


Method	Explanation
Automatically in the ShadowStoreDelete job.	When the defragmentation feature is enabled in the global configuration, defragmentation runs automatically as part of the ShadowStoreDelete job. In this case, the option settings in the global configuration control the behavior of the defragmenter.
On the command line.	You can run the defragmenter on the command line using the isi_sstore defrag command. In this case, the options are set on the command line. See isi_sstore defrag for more information.

The following procedure describes how to prepare for running the defragmenter automatically as part of the ShadowStoreDelete job..

Make sure that defragmentation is enabled and review current global configuration settings as described in previous procedures.

Optionally, run the isi_sstore list -v command to check the fragmentation and storage efficiency scores before defragmentation.

The output is similar to the following:

# isi_sstore list -v
                SIN     lsize     psize       refs   filesize           date    sin type underfull frag score efficiency
4100:0001:0001:0000  66584576   129504K      16256    128128K   Sep 20 22:55   container        no       0.49       0.50
...

Run the ShadowStoreDelete job.
```
# isi job jobs start ShadowStoreDelete [-o HIGH]
```
This job reclaims unused blocks from shadow stores and runs the defragmenter if it is enabled.
Optionally rerun the isi_sstore list -v command to check the fragmentation and storage efficiency scores after defragmentation.
The following results are expected:
- The fragmentation score should be lower after defragmentation.
  If the fragmentation score is not reduced, check if the shadow store underfull flag is true. When the shadow store contains only a small amount of data, the defragmenter may not move the data, and the fragmentation score remains unchanged.
- The efficiency score should be higher after defragmentation.
  The storage efficiency may be reported as low if the shadow store is underfull due to an insufficient sample of containerized data.