zHyperLink: The Holy Grail of Mainframe I/O?

GilbertzHyperLink

By Gilbert Houtekamer, Ph.D.

Now that it has become harder and harder to make the processor faster, IBM is looking for other ways to make their mainframes perform better.

This has resulted in new co-processors for compression and encryption and now also, with the z14 processor, in a new technology called zHyperLink. This new I/O connectivity aims to significantly reduce the I/O response time, while at the same time not increase the processor (CP) load.

This new technology comes with a set of promises and restrictions that will cause you to rethink the design of your storage and replication infrastructure. The days of distance limitations are back, which has big implications for synchronous replication in particular.

Continue reading

HDS Pools Hit the Target in RMF for Hitachi Dynamic Tiering

Gilbert

By Gilbert Houtekamer, Ph.D.

In previous blogs we talked about metrics that we would like to see added to RMF and SMF records. We also discussed the challenges that EMC and HDS face fitting their measurement data in the IBM-defined RMF instrumentation.

A good example of what can be achieved given the constraints is what HDS did for their Hitachi Dynamic Provisioning (HDP) pools. HDP pools are the basis for thin provisioning and dynamic tiering in the Hitachi architecture. An HDP pool consists of a number of array groups. Arrays with different drive technologies can be combined in a pool with dynamic tiering, in a mix that you feel is appropriate for your workload. Continue reading