Determining compression savings for volumes

Storage administrators can analyze an individual volume or all the volumes on a system for the potential capacity savings if compression is used.

About this task

The Comprestimator tool is integrated into the system and is available through the management GUI and command-line interface. The Comprestimator is an application that can be installed on hosts to estimate the capacity savings if compression was used in an environment. However, it requires access to hosts, which a storage administrator might not have. Storage administrators can now use the management GUI or CLI commands to analyze potential compression savings. If the compression savings are beneficial to your environment, you can use volume mirroring to convert volumes to compressed volumes.

If you are using compression in data reduction pools, it is recommended that you also run the Data Reduction Estimator Tool (DRET). This tool also analyzes potential capacity savings that can be provided by other supported data reduction technologies, like deduplication. The tool scans target workloads on all attached storage arrays, consolidates these results, and generates an estimate of potential data reduction savings for the entire system.

Go to https://www-945.ibm.com/support/fixcentral/ to search under FlashSystem 9100 to find the tool and its readme.

To access the Comprestimator tool on the management GUI, select Volumes > Volumes. Right-click the volume or volumes that you want to analyze and select Space Savings > Estimate Compression Savings to get a calculation of the amount of potential compression savings. You can also select Space Savings > Analyze for more detailed report. You can also download the report that is generated.

You can also use the command line interface to run estimates or complete an analysis of compression savings.

Procedure

To analyze a single volume for compression savings, complete these steps:
1. In the command-line interface, enter the following command:
```
analyzevdisk -vdisk_name | -vdisk_id 
```
  where -vdisk_name or -vdisk_name is either the name or identifier for the volume that you want to analyze for compression savings.
2. Analysis results can be displayed after the process completes by issuing the following command:
```
lsvdiskanalysis -vdisk_name | -vdisk_id 
```
  where -vdisk_name or -vdisk_id is either the name or identifier for the volume that you want to analyze for compression savings.
To analyze all the volumes that are currently on the system, complete these steps:
1. In the command-line interface, enter the following command:
```
analyzevdiskbysystem
```
  This command analyzes all the current volumes that are created on the system. Volumes that are created during or after the analysis are not included and can be analyzed individually with the analyzevdisk. Progress for analyzing of all the volumes on system depends on the number of volumes that are being analyzed and results can be expected at about a minute per volume. For example, if a system has 50 volumes, compression savings analysis would take approximately 50 minutes.
2. To check the progress of the analysis, enter the following command:
```
lsvdiskanalysisprogress
```
  This command displays the total number of volumes on the system, the total number of volumes that are remaining to be analyzed, and the estimated time of completion.