Combining performance and capacity in the same system requires that you identify performance workloads that will represent the majority of your I/O, and assume data reduction using inline hardware compression. 

In addition, you must identify capacity workloads that can maximise capacity with modest I/O, and assume data reduction with deduplication and compression. 

Identifying the workload demands enables you to create a balanced high-performance, high-capacity system with a single point of management. As the workload evolves, you might need to migrate between fully allocated and data reduction volumes, so careful monitoring is required. 

## 3.10.8 Evaluating workload using Disk Magic 

Besides using test volumes, and observing actual performance for the application, IBM also has a tool called Disk Magic  that is designed specifically for modeling performance. 

Disk Magic for IBM is a performance analysis and hardware configuration planning tool for IBM storage disk subsystems that runs only on Microsoft Windows (XP or later). It is licensed by IBM from IntelliMagic for exclusive use by IBMers and IBM Business Partners in the selling of new or upgraded IBM disk storage solutions. 

Proper initial sizing greatly helps to avoid future sizing problems. Disk Magic is one tool that is used for sizing and modeling storage subsystems for various open systems environments and various IBM platforms. 

It provides accurate performance and capacity analysis and planning for IBM Spectrum Virtualize products, other IBM storage solutions, and other vendors’ storage subsystems. Disk Magic provides in-depth environment analysis, and is an excellent tool to estimate the performance of a system that is running (DRP) Data Reduction Pools. 

For IBM Business Partners who would like more information about Disk Magic, and the latest version, can be found at the Disk Magic website (login required). 

## 3.11 Availability considerations when configuring the FS9100 

This section highlights the implications storage pool configurations and host volume assignments have on availability. 

This section includes: 

GLYPH<SM590000> Availability considerations when configuring storage pools 

GLYPH<SM590000> Availability considerations for host volume assignments 

## 3.11.1 Availability considerations when configuring storage pools 

Although the FS9100 provides many advantages through consolidation of storage, it is important to understand the implications that various configurations have on defining failure domains within the IBM Spectrum Virtualize Storwize cluster. When you select MDisks for a storage pool, performance is often the primary consideration. However, in many cases, the availability of the configuration is traded for little or no performance gain. 

Remember that IBM Spectrum Virtualize and Storwize must take the entire storage pool offline if a single MDisk in that storage pool goes offline. Consider an example where you 

