Comprestimator is an IBM tool available for most common OS.

Since SVC version 7.6, it's integrated into storage arrays to test the data reduction when using compressed volumes.

Now you can use the SVC command line to evaluate the compression rate on volumes

analyzevdisk - analyzes a specific volume

analyzevdisk [-cancel] <vdisk_ID/vdisk_name>

lsvdiskanalysisprogress - Gives you the progress of the analysis. Helpful if doing the analysis on the entire system

lsvdiskanalysisprogress [-nohdr] [-delim <delimiter]

analyzevdiskbysystem – Analyzes all volumes on system

lsvdiskanalysis - lists the output. Can be listed for a single volume or if no volume identified, lists output for all volumes

lsvdiskanalysis -vdisk_name | -vdisk_id 

SVC> lsvdiskanalysis vol6
id 6
name vol6
state estimated
started_time 150608135446
analysis_time 150608135456
capacity 1.00GB
thin_size 62.18MB
thin_savings 961.82MB
thin_savings_ratio 93.92
compressed_size 12.23MB
compression_savings 49.95MB
compression_savings_ratio 80.33
total_savings 1011.77MB
total_savings_ratio 98.80
accuracy 4.97

To display the compression analysis results for all the volumes on the system, enter this command:

SVC> lsvdiskanalysis
id name  state     analysis_time capacity thin_size thin_savings thin_savings_ratio compressed_size compression_savings compression_savings_ratio total_savings total_savings_ratio accuracy
0  vol0  idle                    1.00GB   0.00MB    0.00MB       0                  0.00MB          0.00MB              0                         0.00MB        0                   0
1  vol1  idle                    1.00GB   0.00MB    0.00MB       0                  0.00MB          0.00MB              0                         0.00MB        0                   0
2  vol2  active                  1.00GB   0.00MB    0.00MB       0                  0.00MB          0.00MB              0                         0.00MB        0                   0
3  vol3  idle                    1.00GB   0.00MB    0.00MB       0                  0.00MB          0.00MB              0                         0.00MB        0                   0
4  vol4  idle                    1.00GB   0.00MB    0.00MB       0                  0.00MB          0.00MB              0                         0.00MB        0                   0
5  vol5  idle                    1.00GB   0.00MB    0.00MB       0                  0.00MB          0.00MB              0                         0.00MB        0                   0
6  vol6  estimated 150608135456  1.00GB   62.18MB   961.82MB     93.92              12.23MB         49.95MB             80.33                     1011.77MB     98.80               4.97
7  vol7  scheduled               1.00GB   0.00MB    0.00MB       0                  0.00MB          0.00MB              0                         0.00MB        0                   0
8  vol8  idle                    1.00GB   0.00MB    0.00MB       0                  0.00MB          0.00MB              0  

lsvdiskanalysis States

• Estimated – Compression ratio has been determined. Give date and time of last run
• Active – Volume is currently being estimated
• Scheduled – Volume is waiting to be estimated
• Idle – Volume has never been estimated and is not scheduled to be estimated