FlashCore Modules recommendations 2.4.5 Considerations for IBM FlashSystem 900 Defining storage For FCM arrays, the number of volumes is also governed by load distribution. 16 to 32  volumes out of a pool with an FCM array are recommended. When choosing volume size, take into account which system (front-end or back-end) will  perform compression. If data is compressed and deduplicated on the front-end SVC, FCMs  will not be able to compress it further, which will result in a 1:1 compression ratio. So, the  back-end volume size should be calculated from the pool physical capacity divided by the  number of volumes (16 or more).  Example: Storwize V7000 Gen3 with 24 x 19.2 TB modules. This configuration will  provide raw disk capacity of 460 TB, with 10+P+Q DRAID6 and one distributed spare,  physical array capacity will be 365 TB or 332 TiB. As it is not recommended to  provision more than 85% of a physical flash, we have 282 TiB. As we do not expect  any compression on FCM (back-end is getting data that is already compressed by  upper levels), we provision storage to upper level assuming 1:1 compression, which  means we create 32 volumes 282TiB / 32 = 8.8 TiB each. If the front-end system is not compressing data, space savings will be achieved with FCM  hardware compression. Use compression estimation tools to determine the expected  compression ratio and use a smaller ratio for further calculations (for example, if you expect  4.5:1 compression, use 4.3:1). Determine the volume size using the calculated effective pool  capacity. Example: Storwize V7000 Gen3 with 12 x 9.6 TB modules. This configuration will  provide raw disk capacity of 115 TB, with 9+P+Q DRAID6 and one distributed spare,  physical capacity will be 85 TB or 78 TiB. As it is not recommended to provision  more than 85% of a physical flash, we have 66 TiB. Compresstimator has shown that  we can achieve 3.2:1 compression ratio, decreasing in and assuming 3:1, we have  66TiB x 3 = 198 TiB of effective capacity. Create 16 volumes, 198TiB / 16 = 12.4  TiB each. If compression raio will be higher than expected, we can create and  provision to front end more volumes. The main advantage of integrating FlashSystem 900 with SAN Volume Controller is to  combine the extreme performance of IBM FlashSystem with the SAN Volume Controller  enterprise-class solution such as tiering, volume mirroring, thin provisioning, IBM Real-time  Compression, and Copy Services. When you configure the SAN Volume Controller/Storwize family system with IBM  FlashSystem storage systems, you must remember the considerations that are described in  this section. IBM FlashSystem 900 supports up to 12 IBM MicroLatencyfi modules. Each IBM  MicroLatency module has a usable capacity of either 1.06 TiB (1.2 TB), 2.62 TiB (2.9 TB), or  5.24 TiB (5.7 TB) of flash storage. IBM MicroLatency modules without the child board are  either half-populated with 1.06 TiB (1.2 TB) or fully populated with 2.62 TiB (2.9 TB). The  optional child board adds another 2.62 TiB (2.9 TB) for a total of 5.24 TiB (5.7 TB).  IBM MicroLatency modules are installed in the IBM FlashSystem 900 based on the following  configuration guidelines: GLYPH<SM590000> A minimum of four MicroLatency modules must be installed in the system. RAID 5 is the  only supported configuration of the IBM FlashSystem 900. Chapter 2. Back-end storage  75