IBM Systems Magazine, Mainframe - September/October 2015 - (Page 42)

ADMINISTRATOR EDITOR'S NOTE: This is part two of a two-part series on the IBM DS8870 storage subsystem on the IBM z13 platform. Read part one in the July/August 2015 issue. Get Into the EXPRESS LANE With FICON New zHPF protocols offer up to a 68 percent reduction in I/O service time for write operations T he IBM z13* system and IBM DS8870 storage subsystem have been designed to deliver on a set of enhancements to meet the ever-increasing demands of transaction processing and cloud, analytics, mobile, social and security. Christopher Colonna is the FICON channel firmware execution team lead for z Systems, IBM Systems. Roger G. Hathorn is a Senior Technical Staff Member for enterprise storage I/O architecture and development, IBM Systems. Harry M. Yudenfriend is an IBM Fellow for storage development and mainframe I/O technology, IBM Systems. Clients have expressed the desire to share inter-switch links (ISLs) between their FICON* I/O traffic and the Fibre Channel Protocol (FCP) Metro Mirror traffic generated from it. This would allow them to not only share the same physical ports and fibers between switches and sites, but also get predictable and repeatable performance with a dynamic routing policy that was lacking with the older static-based routing policies. Both of these attributes would save client money by allowing the reduction in port counts, fibers and the leasing of dark fiber bandwidth between sites. Additionally, the people cost for managing the storage-area network (SAN) fiber performance could also be reduced. With the z13 system, FICON is no longer restricted to the use of static SAN routing policies for cascading FICON directors. This z13 feature that supports dynamic routing in the SAN is called FICON Dynamic Routing (FIDR). It provides the support 42 // SEPTEMBER/OCTOBER 2015 needed to handle the out-of-order conditions that could occur when using dynamic routing policies in the SAN, thus eliminating any possible protocol errors that used to occur if SAN dynamic routing was enabled. Only qualified FICON directors are supported for use with FIDR. Clients are encouraged to check with their SAN provider to make sure the equipment and firmware versions have been qualified. The DS8870 storage subsystem has been qualified to work with the FIDR feature and participate in z/OS* health checks to validate that the configuration is supported by all of the attached equipment. The capability for z Systems* clients to share their fibre channel SANs between FICON traffic and their FCP Metro Mirror traffic can reduce costs. The inability to share ISLs with different routing policies increases costs because it requires additional expense for: ĀÃ 3K\VLFDOÃKDUGZDUHÃLQFOXGLQJÃ switches, switch ports and ISL links ĀÃ ĀÃ ,6/ÃOLQNVÃZKLFKÃUHTXLUHÃFOLHQWVÃ to lease additional dark fibre and bandwidth between sites 3HUVRQQHOÃDQGÃVNLOOVÃWRÃPDQage the complexity, problem determination, identification of hot spots, instrumentation and accounting Even in a FICON-only environment, FIDR and SAN dynamic routing policies enable a better balance of the workload over links with predictable and repeatable performance, which will also reduce costs by simplifying management. SAN dynamic routing policies can better exploit all of the available ISL bandwidth than static routing policies. As a result, ISLs can be driven to higher utilization before incurring queuing delays that would result in longer I/O service times. Static routing policies can assign different ISL routes from power-on-reset (POR) to POR of the SAN fabric. The routes are assigned without any previous knowledge of the traffic that may

Table of Contents for the Digital Edition of IBM Systems Magazine, Mainframe - September/October 2015

Table of Contents
Editor's Desk: Flexible options
IBM Perspective: The full potential of Linux
Infographic: Differentiate your cloud services and drive margins sky-high
Techbits: The P-TECH fast track
Partner PoV: Virtualizing system software can help reduce data center costs
Trends: IBM has the roadmap you need to get to business innovation
Currents: Thanks to mobile apps, users can access IBM z Systems services and data
IT Today: A Cloud IT Optimization Assessment can help determine the right solutions
Case Study: Letters Home: Western Illinois University improves school-to-student interaction with more eye-catching financial aid documents
Cover Story: Linux Breakthrough: New IBM LinuxONE systems are enterprise-grade and built for business-critical applications
Feature: Community Partnership: The new Open Mainframe Project capitalizes on the strengths of z Systems and Linux to foster growth
Feature: A Matter of Standards: The KVM hypervisor extends familiar tools to Linux on the mainframe
Tech Showcase: Understanding VSAM can help you process and access information
Administrator: New zHPF protocols offer up to a 68 percent reduction in I/O service time for write operations
Solutions: Integration Link; SIEM Agent for z/OS
Stop Run: Software engineer notes creative side with musical instruments and choirs
Reference Point - Global Events, Education, Resources for Mainframe
Mainframe Skills Special Report
2016 Mainframe Solutions Edition

IBM Systems Magazine, Mainframe - September/October 2015