The total saving effect achieved by capacity saving, Dynamic Provisioning, and snapshot is displayed in management software. System data (metadata and garbage data for the capacity saving function, Thin Image Advanced metadata) is not included in the Total Efficiency Ratio. These examples show the relationship between the total efficiency and the efficiency achieved by each function when applying deduplication and compression of the capacity saving function.
- The Total Efficiency Ratio and associated efficiency values do not include the total capacity and used capacity of these volumes:
- Journal volumes
- Volumes with the data direct mapping attribute
- Command devices
- Deduplication system data volumes (fingerprint and data store)
- Child volumes used in Thin Image Advanced
- Quorum disks
- Remote command devices
- When a pool is blocked, the values before the pool is blocked are displayed by management software, and the values are updated after the pool is restored.
- When any of these operations is performed, the Total Efficiency Ratio and associated values displayed by management software and CCI might be lower than the actual values:
- Creating LDEVs or increasing the LDEV capacity
- Initializing duplicated data
- Reclaiming zero data page
- Deleting or formatting LDEVs
- Creating snapshots in Thin Image Advanced (pair split operation and virtual clone creation)
- Deleting S-VOLs used in Thin Image Advanced
- Conversion to vClone volumes in Thin Image Advanced
- Conversion to snapshots in Thin Image Advanced
- The Total Efficiency Ratio and associated efficiency values change according to configuration changes and the type of I/O load. The efficiency values are more accurate when I/O loads are not high. You might obtain lower values immediately after performing operations.
- If data is written across the V-VOL, the Total Efficiency Ratio might become less than 1.
- It takes up to 90 minutes to calculate the Total Efficiency Ratio and associated efficiency values.
The following terms are used:
- DRS-VOL
- Data reduction shared volume
- DRS-VOL used capacity
- Used capacity of the data reduction shared volume before applying data saving functions
- Irreducible capacity
- Data capacity that cannot be compressed or deduplicated
- Snapshot defined capacity
- parent volume defined capacity × (the number of pairs + the number of volumes with the vClone attribute)
DRS-VOL used capacity includes the differential data capacity of snapshots.
The following figure shows the total efficiency ratio and the associated efficiency values.
The following figure shows the software saving ratio and the associated efficiency values.
Efficiency values
The total effect displays the data reduction effect information for open systems, excluding pools for mainframe systems. CCI commands contain two types: commands that the data reduction effect information is displayed on a system basis and on a pool basis.
| CCI command items | Terms used in the figures | Descriptions | ||
|---|---|---|---|---|
| Command to display information on a system basis | Command to display information on a pool basis | Displayed item name | ||
|
raidcom get system -key efficiency |
raidcom get pool -key efficiency |
TOTAL_EFF_R | Total efficiency ratio | Displays the ratio of the sum of DRS-VOL capacity and snapshot defined capacity to the final pool used capacity. |
| TLS_R | Data reduction ratio | Displays the ratio of DRS-VOL used capacity to the final pool used capacity. | ||
| PLS_R | Software saving ratio | Displays the ratio of data size before and after the data reduction function is applied to DRS-VOL used capacity. The ratio is calculated based on both data size including irreducible capacity. | ||
| PLS_RECLAIM_R | Software pattern reclaim ratio | Displays the ratio of data size before and after the pattern reclamation process of the data reduction function is applied to DRS-VOL used capacity. | ||
| PLS_CMP_R | Software compression ratio |
Displays the detailed information about PLS_R. Displays the ratio of data size before and after compression is applied to data after pattern reclamation on DRS-VOLs. |
||
| PLS_DDP_R |
Software deduplication ratio Displays the detailed information about PLS_R. |
Displays the ratio of data size before and after deduplication is applied to data after compression on DRS-VOLs. | ||
| PLS_EXCUNCMP_R | Software saving ratio | Displays the ratio of data size before and after the data reduction function is applied to the DRS-VOL used capacity. The ratio is calculated based on both data size excluding irreducible capacity. | ||
| NA | PL_EXCNORED_PRE_USED(MB)* | DRS-VOL used capacity (excluding irreducible capacity) | Displays the DRS-VOL used capacity in MB. This capacity excludes irreducible capacity. | |
| PL_EXCNORED_USED(MB)* | Pool used capacity (excluding irreducible capacity) | Displays the DRS-VOL used capacity in MB after applying the data reduction functions. This capacity excludes irreducible capacity. | ||
| PL_NORED_USED(MB)* | Irreducible capacity | Displays irreducible capacity in MB. | ||
| *This item is only displayed when a system-based command is run. | ||||