IBM DS6000 Series manual Mix of extent pools

blue I/O

preferred path	preferred path
red I/O	blue I/O

red I/O

Rank

	Server 0		Server 1
	blue			red
Extent pool0	Extent pool2		Extent pool3		Extent pool1
1	3	5	5	3	1
	7	9	9	7
11					11
Extent pool4					Extent pool5
blue extent pools					red extent pools

Figure 11-14 Mix of extent pools

Create two general extent pools for all the average workload and the majority of the volumes and subdivide these pools evenly between both processor complexes or servers. These pools contain the majority of the installed ranks in the DS6000. Then you might consider two or four smaller extent pools with dedicated ranks for high performance workloads and their volumes. You may consider defining storage groups accordingly which are congruent to the smaller extent pools.

Consider grouping the two larger extent pools into a single SMS storage group. SMS will eventually spread the workload evenly across both extent pools. This allows a system-managed approach to place data sets automatically in the right extent pools. With more than one DS6000 you might consider configuring each DS6000 in a uniform fashion. We recommend grouping all volumes from all the large extent pools into one large SMS storage group. Cover the smaller, high performance extent pools through discrete SMS storage groups for each DS6000. For example, in a dual logging database environment allow assignment of extent pool0 to the first logging volume and extent pool1 for the second logging volume. Consider a respective channel path configuration which takes preferred paths into account.

11.6 Summary

The DS6000 high performance processor complex configuration is the base for a maximum of host I/O operations per second. The DS6000 can handle I/O rates of about what an ESS 800 can deliver at maximum speed. With the introduction of the smart, switch-based Fibre Channel disk back end, which overcomes the FC-AL arbitration overhead and operates at 2 Gbps speed, the DS6000 provides a better sequential throughput than an ESS 800.

The DS6000 series is designed to deliver enterprise-class storage capabilities in a space efficient, modular design at a low price. It provides a wide capacity range from 16 DDMs up to

240DS6000 Series: Concepts and Architecture