GLYPH<SM590000> Option 2: SVC uses DRP with both compression enabled volumes and allocated volumes, while the IBM FlashSystem 9100 uses fully allocated volumes to provide capacity to SVC. This is not a recommended configuration. The problem with this configuration is that it is very difficult to understand the physical capacity use of the fully allocated volumes. 

GLYPH<SM590000> Option 3: SVC uses fully allocated volumes while the IBM FlashSystem 9100 uses DRP with compressed and deduplicated volumes to provide capacity to SVC. This is a valid configuration, even not the preferred. The problem with this configuration is that SVC can report physical use but does not manage to avoid out-of-space. This option requires careful monitoring of capacity to not run out of space. 

GLYPH<SM590000> Option 4: SVC uses DRP with compression/deduplication enabled and the IBM 

FlashSystem 9100 uses DRP with compressed and deduplicated volumes to provide capacity to SVC. This is a configuration to be avoided since it creates two levels of I/O amplification on metadata. Furthermore, DRP at the bottom layer provides no benefit. 

Note:  The usage of DRP with compressed/deduplicated volumes as SVC back-end requires substantial resources in terms of cache and CPU. To avoid performance issues with entry level Storwize systems like Storwize V5010 and Storwize V5010E, consider using fully allocated volumes unless data reduction is strictly required. 

## 4.7.3 DRP provisioning considerations 

Consider the following practices when planning for DRP implementation. 

## DRP restrictions 

There are some important restrictions that must be taken into consideration when planning for a DRP implementation: 

GLYPH<SM590000> Maximum number of supported DRP is 4 

GLYPH<SM590000> Child Pools are not supported in DRP 

GLYPH<SM590000> VVols are not supported in DRP 

GLYPH<SM590000> Volume shrinking is not supported in DRP with thin/compressed volumes 

GLYPH<SM590000> Non-Disruptive Volume Move (NDVM) is not supported with DRP volumes 

GLYPH<SM590000> The volume copy split of a Volume Mirror in a different I/O Group is not supported for DRP thin/compressed volumes 

GLYPH<SM590000> Image and Sequential mode VDisk are not supported in DRP 

GLYPH<SM590000> No extent level migration is allowed 

GLYPH<SM590000> A maximum of 128,000 extents per Customer Data Volume - per I/O Group 

GLYPH<SM590000> Thus the Pool extent size dictates the maximum physical capacity in a pool - after data reduction. 

GLYPH<SM590000> Recommended Pool size is at least 20 TB 

GLYPH<SM590000> Lower than 1 PB per I/O group 

GLYPH<SM590000> Use 4 GB extent size or above 

GLYPH<SM590000> Your Pool should be no more than 85% occupied 

