IBM Mainframe- Saving costs using Specialty Processors
Mainframes, in spite of various predictions, still form the backbone of many large organizations. But it is also true that IBM is facing stiff competition especially with modern workloads involving Linux, XML and Java. Cost factor is a serious concern when it comes to usage of mainframe – as in other factors including security, reliability and availability, Mainframe still rules the roost. While mainframe hardware costs per se are very high, ISV licensing costs form a huge chunk of expenditure.
MIPS optimization is an ongoing activity in most mainframe shops. But this doesn’t save any of the ISV software licensing costs as they are linked to the overall capacity of the machine – and not the actual workload.
The solution is to turn the focus to exploit the specialty processors – IFL, zAAP, zIIP – offered by IBM. These processors cost significantly less – almost one-fifth – compared to the General purpose processors. These specialty engines “do not count” in software pricing calculations and ISV licensing costs is where the bulk of the savings come from. Upgrade and maintenance cost of ISV software also reduces proportionately. It is important to note that unless used effectively these processors may end up under-utilized or even unutilized – as they are configured as to process only a specific type of workload.
Integrated Facility for Linux (IFL) is a processor used exclusively for Linux load in mainframe – either a Linux LPAR or Linux running under z/VM. It should not be assumed that Linux LPAR would use this IFL by default and a Linux LPAR can still be using general central processors.
z/OS Application Assist Processor (zAAP) is a processor used to run Java applications. zAAP runs with general CPs in a z/OS LPAR. When Java code is detected, z/OS switches that instruction set to the zAAP processor, freeing up the general CP to perform other, non-Java, work. IBM indicates that with later versions of z/OS, all XML System Services validation and parsing that execute in TCB mode (which is problem state mode as in most application workloads), may be eligible for zAAP processing providing significant savings in the near future.
z/OS Integrated Information Processor (zIIP) is a special purpose processor allowing you to optimize database workload functions such as business intelligence (BI), enterprise resource planning (ERP), and customer relationship management (CRM). When certain database code is detected, z/OS switches that instruction set to the zIIP processor, freeing up the general CP to perform other work. z/OS Communications Server exploits the zIIP for eligible IPSec network encryption workloads. Also, XML System Services are enabled to take additional advantage of the zIIP for pre-emptable SRB – eligible XML workloads.
Central Processor (CP) is a processor available to the general operating system and application software. By moving the workload from this to different z/Architecture processors appropriately leads to major cost savings in a mainframe environment.
True to mainframe culture, these specialty processors are not effectively used by default. The system needs to be tuned in such a way – not so straight forward again – as to use the right processors for the right load. ISVs do provide software and tools that enable this process.
Capacity Setting – also called as kneecapping – is another option where the mainframe models or versions are configured to operate slower than their potential speed. It is done by using microcode to insert null cycles into the processor instruction stream. This again is done with the aim of controlling software costs by limiting the mainframe to the minimum level that meets the application requirements.
IBM also provides various forms of Capacity on Demand (CoD) and similar arrangements exist whereby a customer can enable additional CPs at certain times (for example, unexpected peak loads or year-end processing requirements). Today’s mainframe also has capacity provisioning capability to monitor z/OS utilization of system workloads. This feature allows CPUs to be turned on and off dynamically.
Thus effective use of specialty engines and capacity provisioning features, coupled with strong negotiation with ISVs – can provide substantial savings in mainframe environment.