Administrator Guide

Table Of Contents
Supported Hardware Platforms
The following controller series support Data Reduction:
SCv3000 Series (Supports Compression only)
SC4020
SC5020
SC5020F
SC7020
SC7020F
SC8000
SC9000
Compression
Compression reduces the amount of space used by a volume by encoding data. Compression runs daily with Data Progression.
To change the time at which compression runs, reschedule Data Progression. Compression does not run with an on-demand
Data Progression.
When compressed data is read, it is temporarily uncompressed in memory until the read is complete. When compression is
disabled, pages are permanently uncompressed during the next compression cycle, and the original compressed page is deleted
as time and resources permit. When a volume is deleted or a snapshot is coalesced, the related compressed data is also deleted.
Deleted data might create gaps in the compressed page, which can be filled with new compressed data. In addition, compressed
pages are defragmented during Data Progression to remove gaps and use space more efficiently.
The Compression Savings amount is determined by comparing the total amount of space saved from all compressed pages to
the total amount of used space that is eligible for compression. For example, if compression saves 1 GB on a volume with 10 GB
of used space that is eligible for compression, the amount saved is 10 percent.
Apply Data Compression to a Volume
Apply Data Compression to a volume to reduce disk space usage for that volume.
Steps
1. If the Storage Manager Client is connected to a Data Collector, select a Storage Center from the Storage view.
2. Click the Storage tab.
3. In the right pane, click Edit Settings.
The Edit Volume dialog box opens.
4. From the Data Reduction Profile drop-down list, select Compression.
5. Click OK.
Related tasks
Creating Volumes on page 98
Modifying Volumes on page 102
Storage Center Administration
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