IBM DS6000 Series ユーザーズマニュアル

Chapter 11. Performance considerations 

The challenge is obvious: Develop a storage server—from the top with its host adapters down 
to its disk drives—that creates a balanced system with respect to each component within this 
storage server and with respect to their interconnectivity with each other. All this must be 
done while taking into consideration other requirements as well, like investment protection 
and being competitive not only in performance but also with respect to price and reliability.

A further requirement is to keep the life cycle of the product as long as possible due to the 
substantial development costs for an all new product. Furthermore, provide a storage family 
approach with a single management interface and the potential to adopt new technology as it 
develops on a component level. The simple picture suggests that this a more difficult task for 
a storage server than for a host server. Perhaps it became this way with the evolving 
complexity of storage servers.

The IBM Enterprise Storage Server 2105 (ESS) already combined everything mentioned in 
the previous paragraph when it appeared in the marketplace in 1999. Over time the ESS 
evolved in many respects to enhance performance and to improve throughput. Despite the 
powerful design, the technology and implementation used eventually reached its life cycle 
end.

Looking more closely at the components in the ESS and their enhancements from the E20 to 
the F20 to the 800 and 800 Turbo II models, some components reached their architectural 
limits at various levels. This section briefly reviews the most obvious limitations that were 
encountered over time as the other components were enhanced. It has to be noted that the 
ESS 800 is still a very competitive disk storage server which outperforms other storage 
servers in many respects. 

Memory

Memory

Memory

Memory