Storage configuration with IBM i
Typically, when configuring storage for IBM i, the storage administrator will dedicate an entire pool to IBM i. This is a best practice for HDD base storage systems. With -based storage
systems that practice is no longer necessary and can actually become a limitation.
Common practices for -based storage systems in IBM i:
▪System 900 (which is a legacy system, no longer available for selection in Storage Modeller) does not have pools. In a majority of cases, customers only allocate a subset of System 900
capacity to an IBM i host, and use the remaining capacity for other purposes. (That capacity cannot be sized with Capacity Magic).
▪Dedicating a whole pool in System 9200 or Storwize system requires dedicated arrays. With today's large FCMs/SSDs, these arrays should be DRAID-6. However, many small pools with small
DRAID-6 arrays have an unattractive ratio of raw to usable capacity. Consequently, customers favor large arrays in large pools with various volumes attached to either open hosts or IBM i.
▪In SVC configurations, having a large number of pools reduces the write cache efficiency and makes it more difficult to efficiently use then back-end capacity, (but efficiency and
flexibility are key arguments for storage virtualization). There is a trend to use large mixed pools and this trend will accelerate with the adoption of data reduction pools.
In DS8000, having dedicated pools is usually not a concern.