Certain types of DRD-VOLs have high capacity saving values. These types of DRD-VOLs should not be used as the basis of comparison with other DRD-VOLs. These conditions can cause abnormally high capacity saving values on DRD-VOLs:
- DRD-VOLs with large amounts of duplicated data have high capacity saving values due to the deduplication function.
- DRD-VOLs that are replication targets of host-based or storage system-based replication usually have higher capacity saving values than DRD-VOLs that are not replication targets.
If you want to verify the capacity saving effects, check the effect of "software saving" in the following figures. The capacity saving effects can also be obtained on a DRS-VOL with the capacity saving function at the volume creation.
If you want to verify the data reduction effects on the storage system by using the capacity saving function, check "saving effect" in the following figures.
Example 1: Using the capacity saving function (deduplication and compression) on DRS-VOLs
These figures show the capacity saving effect for pools and DRD-VOLs.
The deduplication value shown in [Deduplication Ratio] in the figure might be lower than the actual value because the deduplication data capacity shown in [Deduplication] includes the following data:
- The data on a DP-VOL whose capacity saving setting is compression.
- The data to be deduplicated, but not yet deduplicated.
Example 2: Using the capacity saving function (deduplication and compression) with dedupe and compression on DRD-VOLs
The following table lists the CCI commands that show the capacity saving effect for each pool.
| Command name | Output of command | Item in the figure |
|---|---|---|
| raidcom get pool -key total_saving | SE_SAVING(BLK) | Saving under Saving effect |
| SES(%) | Saving ratio under Saving effect | |
| DATAVOL_USED(BLK) | Data volumes used capacity | |
| raidcom get pool -key software_saving | PLS(%) | Saving ratio under Software saving |
| PL_SAVING(BLK) | Saving under Software saving | |
| CMP(BLK) | Compression under Software saving | |
| DDP(BLK) | Dedup under Software saving | |
| RECLAIM(BLK) | Reclaim under Software saving | |
| SYSTEM(BLK) | System data under Software saving | |
| PL_PRE_USED(BLK) | Capacity before software saving | |
| PRE_CMP_USED(BLK) | Capacity before compression | |
| PRE_DDP_USED(BLK) | Capacity before deduplication |