PowerScale : OneFS : Isilon : How to switch between the Scan Mode and IndexUpdate modes of the FSAnalyze Job
Summary: This Article describes the two FSA Modes available for the cluster to use.
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Instructions
In OneFS 8.2 and later versions FSAnalyze job cab run in two modes:
Index Mode (New Default)
The Index mode relies on Index snapshots and change lists, updates, and walks a global metadata index.
This is enabled by the following gconfig value setting:
Please note that above is the default value for this sysctl.
In this mode phase-7 index_walk is utilized.
Scan Mode (Old style)
The scan mode scans the OneFS file system entirely.
This can be enabled by the following gconfig value setting:
In this mode phase-8 lin_fsa (a.k.a lin_walk) is utilized in place of phase-7.
The (old style) Scan mode also supports (old style) FSAnalyze snapshots. (a.k.a. FSA snapshots)
To turn on FSA snapshot:
Index Mode does not get any benefit from FSA snapshot:
The Index (default) mode of FSA runs faster if an IndexUpdate job is ran before the FSAnalyze job.
The old style FSA snapshots (isi_gconfig fsa.use_snapshot=true) does not have any positive affect in FSA performance in Index mode as well as scan mode, although it creates FSA snapshots.
Index Mode (New Default)
The Index mode relies on Index snapshots and change lists, updates, and walks a global metadata index.
This is enabled by the following gconfig value setting:
isi_gconfig -t job-config jobs.fsa.snap_based_mode=true
Please note that above is the default value for this sysctl.
In this mode phase-7 index_walk is utilized.
Scan Mode (Old style)
The scan mode scans the OneFS file system entirely.
This can be enabled by the following gconfig value setting:
isi_gconfig -t job-config jobs.fsa.snap_based_mode=false
In this mode phase-8 lin_fsa (a.k.a lin_walk) is utilized in place of phase-7.
The (old style) Scan mode also supports (old style) FSAnalyze snapshots. (a.k.a. FSA snapshots)
To turn on FSA snapshot:
isi_gconfig fsa.use_snapshot=true
Index Mode does not get any benefit from FSA snapshot:
The Index (default) mode of FSA runs faster if an IndexUpdate job is ran before the FSAnalyze job.
The old style FSA snapshots (isi_gconfig fsa.use_snapshot=true) does not have any positive affect in FSA performance in Index mode as well as scan mode, although it creates FSA snapshots.
Article Properties
Article Number: 000205111
Article Type: How To
Last Modified: 03 Apr 2025
Version: 2
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