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Data Progression and storage profile selection
50 Dell EMC SC Series: Best Practices with VMware vSphere | 2060-M-BP-V
11.2.1 Data Reduction Input
Within the advanced volume settings, the Data Reduction Input setting can be specified to control which
pages are eligible for data reduction.
Advanced volume settings showing the Data Reduction Input selection
All Snapshot Pages: All frozen pages in the lowest tier of the system that are part of a snapshot, are eligible
for data reduction. If using a single-tiered system, such as a replication target system, all frozen pages are
eligible. This setting yields the highest reductions, however there is a performance tradeoff of higher latency
due to any accessed pages being decompressed as they are accessed.
Inaccessible Snapshot Pages: Only frozen inaccessible pages are eligible for data reduction. These pages
are kept only as part of a snapshot for recovery purposes and are not accessible by the host. This setting
yields the lowest reductions however it has the best performance since no host-accessible pages are
compressed or deduplicated.
Caution: When initially enabling compression on a system, the Data Progression total running time may be
extended and could result in the cycle continuing into regular business hours. Administrators should adjust
the Data Progression settings within the system settings to limit the maximum run time, or limit the number of
volumes to be compressed each day.
For more information about the data reduction feature, read the white paper, Dell Storage Center OS 7.0 Data
Reduction with Deduplication and Compression.