System z: I/O Interoperability Evolution – From Bus & Tag to FICON

Since the introduction of the S/360 Mainframe in 1964 there has been a gradual evolution of I/O connectivity that has taken us from copper Bus & Tag to fibre ESCON and now FICON channels.  Obviously during this ~50 year period there have been exponentially more releases of Mainframe server and indeed Operating System.  In this timeframe there have been 2 significant I/O technology milestones.  Firstly, in 1990, ESCON was part of the significant S/390 announcement (MVS/ESA), where migration to ESCON was a great benefit, if only for replacing the heavy and big copper Bus & Tag channels.  Secondly, even though FICON was released in the late 1990’s, in 2009 IBM announced that the z10 would be the last Mainframe server to support greater than 240 native ESCON channels.  Similarly IBM declared that the last zEnterprise server to support ESCON channels are the z196 and z114 servers.  Each of these major I/O evolutions required a migration philosophy and not every I/O device would be upgraded to support either native ESCON of FICON channels.  How did customers achieve these mandatory I/O upgrades to safeguard IBM Mainframe Server and associated Operating System longevity?

In 2009 it was estimated ~20% of all Mainframe customers were using ESCON only I/O infrastructures, while only ~20% of all Mainframe customers were deploying a FICON only infrastructure.  Similarly ~33% of z9 and z10 systems were shipped with ESCON CVC (Block Multiplexor) and CBY (Byte Multiplexor) channels defined, while ~75% of all Mainframe Servers had native ESCON (CNC) capability.  From a dispassionate viewpoint, clearly the migration from ESCON to FICON was going to be a significant challenge, while even in this timeframe, there was still use of Bus & Tag channels…

One of the major strengths of the IBM Mainframe ecosystem is the partner network, primarily software (ISV) based, but with some significant hardware (IHV) providers.  From a channel switch viewpoint, we will all be familiar with Brocade, Cisco and McData, where Brocade acquired McData in 2006.  However, from a channel protocol conversion viewpoint, IBM worked with Optica Technologies, to deliver a solution that would allow the support for ESCON and Bus & Tag channels to the FICON only zBC12/zEC12 and future Mainframe servers (I.E. z13, z13s).  Somewhat analogous to the smartphone where the user doesn’t necessarily know that an ARM processor might be delivering CPU power to their phone, sometimes even seasoned Mainframe professionals might inadvertently overlook that the Optica Technologies Prizm solution has been or indeed is still deployed in their System z Data Centre…

When IBM work with a partner from an I/O connectivity viewpoint, clearly IBM have to safeguard that said connectivity has the highest interoperability capability with bulletproof data exchange attributes.  Sometimes we might take this for granted with the ubiquitous disk and tape subsystem suppliers (I.E. EMC, HDS, IBM, Oracle), but for FICON conversion support, Optica Technologies was a collaborative partner for IBM.  Ultimately the IBM Hardware Systems Assurance labs deploy their proprietary System Assurance Kernel (SAK) processes to safeguard I/O subsystem interoperability for their System z Mainframe servers.  Asking that rhetorical question; when was the last time you asked your IHV for site of their System Assurance Kernel (SAK) exit report from their collaboration with IBM Hardware Systems Assurance labs for their I/O subsystem you’re considering or deploying?  In conclusion, the SAK compliant, elegant, simple and competitively priced Prizm solution allowed the migration of tens if not hundreds of thousands of ESCON connections in thousands of Mainframe data centres globally!

With such a rich heritage of providing a valuable solution to the global IBM Mainframe install base, whether the smallest or largest, what would be next for Optica Technologies?  Obviously leveraging from their expertise in FICON channel support would be a good way forward.  With the recent acquisition of Bus-Tech by EMC and the eradication of the flexible MDL tapeless virtual tape offering, Optica Technologies are ideally placed to be that small, passionate and eminently qualified IHV to deliver a turnkey virtual tape solution for the smaller and indeed larger System z user.  The Optica Technologies zVT family leverages from the robust and heritage class Prizm technology, delivering an innovative family of virtual tape solutions.  The entry “Virtual Tape In A Box” zVT 3000i provides 2 FICON channel interfaces and 4 TB uncompressed internal RAID-5 disk space, seamlessly interfacing with all System z supported tape devices (I.E. 3490, 3590) and processes.  A single enterprise class zVT 5000-iNAS node delivers 2 FICON channel interfaces, NFS storage capacity from 8TB to 1PB in a single frame with standard deduplication, compression, replication and encryption features.  The zVT 5000-iNAS is available with multi-node configuration support for additional scalability and resiliency.  For those customers wishing to deploy their own choice of NFS or FC storage subsystem, the zVT 5000-FLEX allows such connectivity accordingly.

In conclusion, sometimes it’s all too easy to take some solutions for granted, when they actually delivered a tangible and arguably priceless solution in the evolution of your organizations System z Mainframe server journey from ESCON, if not Bus & Tag to FICON.  Perhaps the Prizm solution is one of these unsung products?  Therefore, the next time you’re reviewing the virtual tape market place, why wouldn’t you seriously consider Optica Technologies, given their rich heritage in FICON channel interoperability?  Given that IBM chose Optica Technologies as their strategic partner for ESCON to FICON migration, seemingly even IBM might have thought “nobody gets fired for choosing…”!

System z MLC Pricing Increases: Look After The Pennies…

Recently IBM announced ~4% price increases in z/OS Monthly License Charges (MLC) for selected Operating System and Middleware software programs and associated features. Specifically, price increases will apply to the VWLC, AWLC, EWLC, AEWLC, PSLC, FWLC and TWLC pricing metrics. Notably, SDSF price increases will be ~20% with Advanced Function Printing (AFP) product price increases of ~13-24%. In a global economy where inflation rates for The USA and Western Europe are close to 0%, one must draw one’s own conclusions accordingly. Lets’ not forget that product version changes typically have an associated price increase. From a contractual viewpoint, IBM only have to provide 90 days advance notice for such price changes, in this instance, IBM provided 150+ days advanced notice.

Price increases are inevitable and as always, it’s better to be proactive as opposed to reactive to such changes. As always, the old proverbs always make good sense and in this instance, “look after the Pennies and the Pounds will look after themselves”! This periodic IBM price increase is inevitable, but is not the underlying issue for controlling System z software costs. For many years, since 1994 to be precise, when IBM introduced Parallel Sysplex License Charges (PSLC), the need for IBM Mainframe users to minimize MSU usage has been of high if not critical importance. Nothing has changed in this 20+ year period and even though IBM might have introduced Sub-Capacity and specialty engines to minimize chargeable MSU usage, has each and every System z user optimized their MSU usage? Ideally this would not be a rhetorical question, rather being a “Golden Rule”, where despite organic CPU capacity increases of ~10% per annum, a System z environment could maintain near static IBM MLC software costs.

I have written several blog entries and presented on this subject matter over the years, for example:

The simple bottom line is that System z MLC software accounts for ~20-35% of the overall System z TCO, typically being the #1 expenditure item. For that reason alone, it’s incumbent for each and every System z user to safeguard they have the technical and commercial skills in place to manage this cost item, not as an afterthought, but inbuilt into each and every System z process, from application design, through to that often neglected afterthought, application tuning.

Many System z organizations might try to differentiate between a nuance of System and Application tuning, but such a “not my problem” type attitude is not acceptable and will be imposing a significant financial burden on each and every organization.

A dispassionate and pragmatic approach is required for optimizing System z CPU usage. In this timeframe, let’s examine the ~20% SDSF price increase. IBM will quite rightly state that in conjunction with their z/OS 2.2 release, there are significant SDSF product function advancements, including zIIP offload, REXX interoperability and increased information delivery. However are such function improvements over and above the norm and not expected as a Business As Usual (BAU) product improvements, which should be included in the Service & Support (S&S) or Monthly License Charges (MLC) paid for software?

In October 2013 I wrote a blog entry; Mainframe ISV Software: Is Continuous Product Improvement Always Evident? The underlying message was that an ISV should deliver the best product they can, for each and every release, without necessarily increasing software costs. In this particular instance, the product was an SDSF equivalent, namely (E)JES, which many years ago delivered all of the function incorporated in SDSF for z/OS 2.2, but for a fraction of the cost…

As of 1 November 2015, IBM will start billing cycles for Country Multiplex Pricing (CMP), which requires the October 2015 version of SCRT, namely V23R10. A Multiplex is defined as a collection of all System z servers in one country, measured as one System z server for software sub-capacity reporting. Sub-Capacity program utilization peaks across the Multiplex will be measured, as opposed to separate peaks by System z servers. CMP also provides the flexibility to move and run workloads anywhere with the elimination of Sysplex aggregation pricing rules.

Migrating to CMP is focussed on CPU capacity growth and flexibility going forward. Therefore System z users should not expect price reductions for their existing workloads upon CMP deployment. Indeed there are CMP deployment considerations. A CMP MSU baseline (base) needs to be established, where this MSU Base and associated MLC Base Factor is established for each sub-capacity MLC product and each applicable feature code. These MSU and MLC bases represent the previous 3 Month averages reported by SCRT before commencing CMP. Quite simply, to gain the most from CMP, the System z user must safeguard that their R4HA for each and every MLC product is optimized, before setting the CMP baseline, otherwise CMP related cost savings going forward are likely to be null.

From a very high-level management viewpoint, we must observe that IBM are a commercial organization, and although IBM provide mechanisms for controlling cost going forward, only the System z user can optimize System z MLC cost for their organization. Arguably with CMP, Soft-Capping isn’t a consideration, it’s mandatory.

Put very simply, each and every System z user can safeguard that they look after the Pennies (Cents) and the Pounds (Euros, Dollars) will look after themselves by paying careful attention to System z MLC software costs. Setting a baseline of System z MLC costs is mandatory, whether for the first time, or to set a new baseline for CMP deployment. Maintaining or lowering this System z MLC cost baseline should or arguably must be the objective going forward, even when considering 10% organic CPU growth, each and every year. System z decision-makers and managers must commit to such an objective and safeguard the provision of adequately skilled personnel to optimize such a considerable TCO cost line item (I.E. MLC @ ~20-35% of System z TCO). In an ecosystem with technical resources including DBA, Systems Programmer, Capacity Planner, Application Personnel, Performance Tuning, et al, why wouldn’t there be a specialist Software Cost Manager?

Let’s consider how even an inexperienced System z user can maintain a baseline of System z MLC costs, even with organic CPU capacity growth of 10% per annum:

  • System z Server Upgrade: Higher specification CPU chips or Technology Transition Offering (TTO) pricing metrics deliver 10%+ cost per MSU benefits.
  • System z Specialty Engines: Over time, more and more application workload can be offloaded to zIIP processors, with no sub-capacity MLC software charges.
  • System z Software Version Upgrades: Major subsystems such as CICS, DB2, IMS, MQSeries and WebSphere deliver opportunity to lower cost per MSU; safeguard such function exploitation.
  • Application Tuning: Whether SQL, COBOL, Java, et al, or the overall I/O subsystem, safeguard that latest programming techniques and I/O subsystem functions are exploited.
  • New Application Deployment: As and when possible, deploy new or convert existing workloads to benefit from the optimal MLC pricing metric; previously zNALC, nowadays zCAP.
  • Technical & Commercial Skills Currency: Safeguard personnel have the latest System z software pricing knowledge, ideally from an independent 3rd party such as Watson & Walker.

In conclusion, as householders we have the opportunity to optimize our cost expenditure, choosing and switching between various major cost items such as financial, utility and vehicle products. As System z users, we don’t have that option, only IBM provide System z servers and associated base architecture, namely the most expensive MLC software products, z/OS, CICS, DB2, IMS and WebSphere/MQ. However, just as we manage our domestic budgets, reducing power usage, optimizing vehicle TCO and getting more bang from our buck for financial products various, we can and must deliver this same due diligence for our System z MLC TCO. With industry averages of ~$500-$1000 per MSU for z/OS MLC software and associated annual expenditure measured in many millions, why wouldn’t any System z user look to deliver 10%+ cost per MSU optimization, year-on-year for their organization?

Clearly the cost of doing nothing in this instance, is significant, measured in magnitudes of millions, each and every year. Hence for System z MLC TCO optimization, looking after the Pennies is more than worthwhile, while the associated benefit of the Pounds, Euros or Dollars looking after themselves is arguably priceless.

z13 WLC Software Pricing Updates: Are You Ready?

Along with the z13 hardware announcement were several very obvious WLC pricing announcements, but more importantly, two hidden Statements Of Direction (SOD) or pre-announcements.

I guess we can all remember the “zSeries Technology Dividend” where put simply, when upgrading zSeries servers, users would benefit from a ~10%+ software price versus performance benefit.  Does anybody still remember the IBM Mainframe Charter from 2003?  That was the document that first referenced this price/performance benefit, which became known as the “technology dividend”.  Specifically, this document stated:

IBM lowered MSU values incorporated in the z990 microcode by approximately 10 percent, resulting in IBM software savings for IBM zSeries software products with MSU-based pricing.  These reduced MSUs do not indicate a change in machine performance. Superior performance and technology within the z990 has allowed IBM to provide improved software prices for key IBM zSeries operating system and middleware software products.

Put really simply, for z990, z9 and z10 server upgrades, IBM delivered this ~10% benefit with faster CPU chips.  Therefore, no noticeable impact on Software Pricing, Capacity Planning or Performance Measurement processes.  However, with the z196/z114, this ~10% benefit could no longer be delivered by CPU chip hardware speed enhancements.  To compensate, IBM introduced the Advanced Workload License Charges (AWLC) pricing regime.  AWLC is an evolution of the Variable (VWLC) pricing regime, lowering per MSU costs for WLC eligible products (E.g. z/OS, CICS, DB2, IMS, WebSphere/MQ, et al).  Hence delivering the ~10% price/performance benefit when upgrading from a z10 to a z196 or z114 (AEWLC) server.

Of course, when upgrading to the zEC12 or zBC12, further refinement of AWLC pricing was required, to deliver this the ~10% price/performance benefit.  Hence, IBM introduced the AWLC Technology Transition Offerings (TTO), lowering AWLC prices for zXC12 and now z13 zSeries servers.

For z13, IBM announced the following z13 AWLC Technology Transition Offerings:

  • Technology Update Pricing for the IBM z13 (TU3): When stand-alone z13 servers are priced with AWLC, or when all the servers in an aggregated Sysplex or Complex are z13 servers priced with AWLC, these servers receive a reduction to AWLC pricing which is called.  Quantity of z13 Full Capacity MSUs for a stand-alone server, or the sum of Full Capacity MSUs in an actively coupled Parallel Sysplex or Loosely Coupled Complex made up entirely of z13 servers.  AWLC discounts range from 4% (4-45 MSU) to 14% (5477+ MSU).
  • AWLC Sysplex Transition Charges (TC2): When two or more machines exist in an aggregated Sysplex or Complex & at z13, zEC12, or zBC12 server & at least one is a z196 or z114 server, with no older technology machines included, they will receive a reduction to AWLC pricing across the aggregated Sysplex or Complex. This reduction provides a portion of the benefit related to the Technology Update Pricing for AWLC (TU1) based upon the proportion of zEC12 or zBC12 server capacity in the Sysplex or Complex.  AWLC discounts range from 0.5% (0-20% z13/zXC12 MSU) to 4.5% (81%-<100% z13/zXC12 MSU).
  • AWLC Sysplex Transition Charges (TC3): When two or more machines exist in an aggregated Sysplex or Complex & at least one is a z13 server & at least one is a zEC12 or zBC12 server, with no older technology machines included, they will receive a reduction to AWLC pricing across the aggregated Sysplex or Complex. This reduction provides a portion of the benefit related to the IBM z13 TU3 offering, based on the total Full Capacity MSU of all z13, zEC12, & zBC12 Machines in the Sysplex or Complex.  AWLC discounts range from 2.8% (4-45 MSU) to 9.8% (5477+ MSU).

These AWLC software pricing announcements are Business As Usual (BAU) and to be expected, but if we dig slightly deeper into the z13 announcements, we will find two other pre-announcements of interest!

Since introducing sub-capacity and WLC pricing regimes, IBM have continually evolved zSeries software sub-capacity pricing mechanisms, with zNALC, AWLC, IWP and more recently MWP offerings.  From a generic viewpoint, with the exception of zNALC, a niche new workload price offering, these pricing announcements did not challenge the “status quo”, where aggregated MSU and large LPAR structures were the ideal.  So why might the upcoming z13 (E.g. Q2 2015) pricing announcements be of note?  Primarily because they challenge the notion of having separate structural entities (I.E. Sysplex Coupled zSeries Servers & LPARS) for existing and new workloads.

Country Multiplex Pricing (CMP): A major evolution, essentially eliminating prior Sysplex pricing rules, requiring that systems be interconnected and/or sharing the same data in order to be eligible for aggregation of MLC software pricing charges.  A Multiplex is defined as the collection of all z Systems within a country.  Therefore, sub-capacity usage will be measured & reported as a single machine, regardless of the connectivity or data sharing configurations.  A new sub-capacity reporting tool is being implemented & clients should expect a transition period as the new pricing model is implemented.  This should allow flexibility to move & run work anywhere, eradicating multiple workload peaks when workloads move between machines.  Ultimately the cost of growth is reduced with one price per product based on MLC capacity growth anywhere in the country.CMP should facilitate for flexible deployment and movement of business workloads between all zSeries Servers located within a country, without impacting MLC billing.  For the avoidance of doubt, this will assist the customer in safeguarding they don’t encounter duplicate MLC peaks as a result of moving an LPAR workload from one zSeries Server to another.  It also removes all Sysplex aggregation considerations, Single Version Charging (SVC) time limits and Cross Systems Waivers (CSW).  Most notably, the cost per MSU for additional capacity will be optimized, being based upon total Multiplex MSU capacity.

IBM Collocated Application Pricing (ICAP): Previously, new applications (zNALC) required a separate LPAR to avoid increases in other MLC software charges.  ICAP facilitates new eligible applications be charged as if they are running in a dedicated environment.  Technically they are integrated with other (non-eligible) workloads.  Software supporting the new application will not impact the charges for other MLC software collocated in the same LPAR.  ICAP appears as an evolution of the Mobile Workload Pricing (MWP) for z/OS pricing mechanism.  ICAP will use an enhanced MWRT, implemented as a z/OS application.  ICAP applies to z13, zXC12, z196/z114 servers.  IBM anticipates that ICAP will deliver zNALC type price benefit, discounting ~50% of ICAP eligible software MSU.

Seemingly IBM have learned from the lessons of IWP, where at first glance, software discounts were attractive, but not at the cost of a separate LPAR.  From a reporting viewpoint, there are similarities to Mobile Workload Pricing for z/OS (MWP), but most notably, pricing is largely zNALC based.  Therefore collocating new workloads in the same LPAR as existing workloads, but with the best price performance of any pricing regime, except zNALC, which is a niche and special edition software pricing metric.

In conclusion, CMP and ICAP are notable WLC pricing regime updates, because they do challenge the status quo of MSU aggregation via Sysplex coupled servers and the ability to collocate new and existing workloads in the same LPAR.  On the one hand, simplified pricing considerations from a granular per MSU cost viewpoint.  However, to optimize price versus performance, arguably the savvy Data Centre will now require a higher level of workload management, safeguarding optimum MSU capacity usage and associated performance.

zPrice Manager is an evolution of the typical soft-capping approach, which can be IBM function based, namely Defined Capacity (DC) or Group Capacity Limit (GCL), or ISV product based.  ISV products typically allow MSU management with dynamic MSU capacity resource management between LPAR, LPAR Group & CPC structures, ideally with Workload Manager (WLM) interaction.  If plug & play simple MSU management is required, these traditional IBM or 3rd party ISV approaches will still work with CMP and ICAP, but will they maximize WLC TCO?

The simple answer is no, because CMP allows the movement of workloads between zSeries Servers.  Therefore if WLC product (I.E. z/OS, CICS, DB2, IMS, WebSphere/MQ) pricing is to be country wide, and optimum WLM performance is to be maintained, a low level granularity of MSU management is required.

zPrice Manager from zIT Consulting allows this level of WLC software product management, with a High Level REXX programmatic interface, and the ability to store real life MSU profile data as callable REXX variables.  Similar benefits apply to ICAP workloads, where different WLM policies might be required for the same WLC product, deployed on the same collocated workload LPAR.  Therefore the savvy data centre will safeguard they optimize MSU TCO via MWP and/or ICAP pricing regimes, without impacting business application performance.

In conclusion, the typical z13 AWLC software pricing updates are Business As Usual (BAU) and can be implemented, as and when required and without consideration.  Conversely, CMP and ICAP can deliver significant future benefit and should be considered in zSeries Server capacity planning forecasts.

Bottom Line Recommendation: Each and every zSeries Server user, whether large or small, should initiate contact with their IBM account teams, for CMP and ICAP briefings, allowing them to consider how they might benefit from these new WLC software pricing regimes.

The IBM Mainframe – 50 Years & Counting

On 7 April 1964 IBM announced the System/360, which is now recognized as the first IBM Mainframe computer system.  IBM Board Chairman Thomas J. Watson Jr. called the event the most important product announcement in the company’s history.  At a press conference at the IBM Poughkeepsie facilities, Mr. Watson said:

“System/360 represents a sharp departure from concepts of the past in designing and building computers. It is the product of an international effort in IBM’s laboratories and plants and is the first time IBM has redesigned the basic internal architecture of its computers in a decade. The result will be more computer productivity at lower cost than ever before. This is the beginning of a new generation, not only of computers, but of their application in business, science and government.”

More than 100,000 businessmen in 165 American cities today attended meetings at which System/360 was announced.  50 years later, I wonder whether there are 100,000 people that work with the IBM Mainframe in The USA and maybe globally…

During this 50 year evolution, the IBM Mainframe has seen opinion polarize, sometimes from the same person:

  • In March 1991, Stewart Alsop stated “I predict that the last mainframe will be unplugged on March 15, 1996.”
  • In February 2002, Stewart Alsop stated “It’s clear that corporate customers still like to have centrally controlled, very predictable, reliable computing systems, exactly the kind of systems that IBM specializes in.”

Obviously the IBM Mainframe server is still here and just like in 1964, in the early 1990’s it did evolve into just another server on the distributed network and the use of routers, incorporating POSIX compliance and so on…

As we all know, the IBM Mainframe has always evolved, continues to evolve and in theory, and often in real-life, can run any workload.

Let’s reprise some of the notable IBM Mainframe models and associated functions since April 1964:

Family Name Announced Notable Function Introduction
S/360 April 1964 24-bit addressing (32-bit architecture)
S/360 August 1965 Virtual storage
S/360 January 1968 High speed cache
S/370 June 1970 Disk & printer support
S/370 August 1972 Virtual storage & multi-processor support
S/370 XA June 1983 Extended storage 24-bit/31-bit addressing
S/390 ESA September 1990 ESA & OS/390 operating systems
zSeries (zArchitecture) October 2000 z operating systems, 24/31/64-bit   addressing supported concurrently
zSeries z9 EC July 2005 zIIP specialty engine
zSeries z10 EC February 2008 High capacity/performance (quad core CPU chip)
z196 (zEnterprise) July 2010 96-way core design & distributed systems integration (zBX)
zEC12 August 2012 Integrated platform for cloud computing, integrated OLTP & data warehousing

It’s interesting to note that the purchase price of an IBM mainframe is about the same, comparing 1964 to 2014, let’s say~$100,000.  Of course, you can’t compare the feeds and speeds of these machines, they’re exponentially different.  However, just as the S/360 in 1964 played a pivotal part in shaping data processing for that decade, subsequent evolutions of the IBM Mainframe follow in that tradition, lowering the cost of IT and simplifying business management.

I’m sure a lot of us have enjoyed our time working with the IBM Mainframe server and long may that be the case, for future generations of IT professionals.

IBM Mainframe: Workload License Charges (WLC) Pros & Cons

It is estimated that less than half of eligible IBM Mainframe customers deploy the VWLC pricing mechanism, which in theory, is the lowest cost IBM software pricing metric.  Why?  In the first instance, let’s review the terminology…

Workload License Charges (WLC) is a monthly software license pricing metric applicable to IBM System z servers running z/OS or z/TPF in z/Architecture (64-bit) mode.  The fundamental ethos of WLC is a “pay for what you use” mechanism, allowing a lower cost of incremental growth and the potential to manage software cost by managing associated workload utilization.

WLC charges are either VWLC (Variable) or FWLC (Flat).  Not all IBM Mainframe software products are classified as VWLC eligible, but the major software is, including z/OS, CICS, DB2, IMS and WebSphere MQ, where these products are the most expensive, per MSU.  What IBM consider to be legacy products, are classified as FWLC.  More recently a modification to the VWLC mechanism was announced, namely AWLC (Advanced), strictly aligned with the latest generation of zSeries servers, namely zEC12, z196 and z114.  For the smaller user, the EWLC (Entry) mechanism applies, where AEWLC would apply for the z114 server.  There is a granular cost structure based on MSU (CPU) capacity that applies to VWLC and associated pricing mechanisms:

Band MSU Range
Base 0-3 MSU
Level 0 4-45 MSU
Level 1 46-175 MSU
Level 2 176-315 MSU
Level 3 316-575 MSU
Level 4 576-875 MSU
Level 5 876-1315 MSU
Level 6 1316-1975 MSU
Level 7 1976+ MSU

Put simply, as the MSU band increases, the related cost per MSU decreases.

IBM Mainframe users can further implement cost control by specifying how much MSU resource they use by deploying Sub-Capacity and Soft Capping techniques.  Defined Capacity (DC) allows the sizing of an LPAR in MSU, and so said LPAR will not exceed this MSU amount.  Group Capacity Limit (GCL) extends the Defined Capacity principle for a single LPAR to a group of LPARs, and so allowing MSU resource to be shared accordingly.  A potential downside of GCL is that is one LPAR of the group can consume all available MSU due to a rogue transaction (E.g. loop).

Sub-Capacity software charges are based upon LPAR hardware utilization, where the product runs, measured in hourly intervals.  To smooth out isolated usage peaks, a Rolling 4-Hour Average (R4HA) is calculated for each LPAR combination, and so software charges are based on the Monthly R4HA peak of appropriate LPAR combinations (I.E. where the software product runs) and not based on individual product measurement.

Once a Defined Capacity LPAR is deployed, this informs WLM (Workload Manager) to monitor the R4HA utilization of that LPAR.  If the LPAR R4HA utilization is less than the Defined Capacity, nothing happens.  If the LPAR R4HA utilization exceeds the Defined Capacity, then WLM signals to PR/SM and requests that Soft Capping be initiated, constraining the LPAR workload to the Defined Capacity level.

If a user chooses a Sub-Capacity WLC pricing mechanism, they will be required by IBM to submit a monthly Sub-Capacity Reporting Tool (SCRT) report.  Monthly WLC invoices are based upon hourly utilization metrics of LPAR hardware utilization, where the software product executes.  The cumulative R4HA and bottom line WLC billing metric is calculated for each product and associated LPAR group and not based on individual product measurement.

Bottom Line: From a Soft Capping viewpoint, the customer only pays for WLC software based upon the Defined Capacity (DC) or Rolling 4-Hour Average (R4HA), whichever is the lowest.  So whether a customer uses Soft Capping or not, in all likelihood, there will be occasions when their workload R4HA is lower than their zSeries server MSU capacity.

So, at first glance, VWLC seems to provide a compelling pricing metric, based upon Sub-Capacity and a pay for what you use ethos, and so why wouldn’t an IBM Mainframe user deploy this pricing metric?

The IBM Planning for Sub-Capacity Pricing (SA22-7999-0n) manual states “For IBM System z10 BC and System z9 BC environments, and z890 servers, EWLC pricing is the default for z/OS systems, and Sub-Capacity pricing is always the best option.  For IBM zEnterprise 114, environments, AEWLC pricing is the default for z/OS systems, and Sub-Capacity pricing is always the best option.  For IBM zEnterprise 196, System z10 EC and System z9 EC environments, and other zSeries servers, Sub-Capacity pricing is cost-effective for many, but not all, customers.  You might even find that Sub-Capacity pricing is cost effective for some of your CPCs, but not others (although if you want pricing aggregation, you must always use the same pricing for all the CPCs in the same sysplex)”.

Conclusion: For all small Mainframe users qualifying for the EWLC (AEWLC) pricing metric, arguably this pricing mechanism is mandatory.  For the majority of larger Mainframe users, the same applies, although a granularity of adoption might be required.  IBM also have a disclaimer “Once you decide to use Sub-Capacity pricing for a specific operating system family, you cannot return to the alternative pricing methods for that operating system family on that CPC.  For example, once you select WLC you may not switch back to PSLC without prior IBM approval”.  However, the requisite contractual exit clause option does exist; the customer can switch back to the PSLC pricing metric.

Some IBM Mainframe users might object to a notion of Soft Capping, relying upon their tried and tested methodology of LPAR management via the number of CPs allocated and associated PR/SM Weight.  This is seemingly a valid notion and requirement, prioritizing performance ahead of cost optimization.

Conclusion: As previously indicated, with VWLC, SCRT invoices are generated upon a premise of the customer only pays for WLC software based upon the Defined Capacity (DC) or Rolling 4-Hour Average (R4HA), whichever is the lowest.  So the VWLC pricing mechanism should deliver a granularity of cost savings, typically higher for a Soft Capping environment.

Some IBM Mainframe users might just believe that nothing can match their Parallel Sysplex Licensing Charge (PSLC) mechanism, first available in the late 1990’s, which might be attributable to other 3rd party ISV’s who cannot and will not allow for their software to be priced on a Sub-Capacity basis.  In reality, adopting the VWLC pricing mechanism delivers ~5% cost savings when compared with PSLC, as indicated by the IBM Planning for Sub-Capacity Pricing Manual (SA22-7999-0n) and related Sub-Capacity Planning Tool (SCPT).

Conclusion: Adopting Sub-Capacity based pricing metrics can only be a good thing.  If your 3rd party ISV supplier doesn’t recognise Sub-Capacity pricing, whether MIPS or MSU based, perhaps you should consider your relationship with them.  Regardless, the z10 server was the last IBM Mainframe to incorporate the “Technology Dividend” solely based on faster CPU chips.  The lower cost WLC pricing metric is now only available with the AWLC and related (E.g. AEWLC) pricing metrics, as per the z196, z114 and zEC12 servers.

Some customers might state that there is a lack of function or granularity of policy definition for IBM supplied Soft Capping (E.g. DC, GCL) or Workload Management (WLM) techniques.  To some extent this is a valid argument, but wasn’t it forever thus with IBM function?  Sub-Capacity implementation is possible via IBM, as is Workload Management (WLM), Soft Capping or not, but should the customer require extra functionality, 3rd party software solutions are available.

The zDynaCap software solution from zIT Consulting delivers a “Capacity Balancing” mechanism, integrating with R4HA and WLM methodologies, but constantly monitoring MSU usage to determine whether CPU resource can be reallocated to Mission & Time Critical workloads, based upon granular customer policies.  The only guarantee in a multiple LPAR environment, for a Mission & Time Critical LPAR to receive all available MSU resource, Soft Capping or not, is to inactivate all other LPARs!  Clearly this is not an acceptable policy for any installation, and so a best endeavours policy applies for PR/SM DC, GCL and Weight settings.

Conclusion: z/OS workloads change constantly, whether the time of day (E.g. On-Line, Batch) or period of the year (E.g. Weekly, Monthly, Quarterly, Yearly) or just by customer demand (E.g. 24 Hour Transaction Application).  Therefore a dynamic MSU management solution such as zDynaCap is arguably mandatory, implementing the optimum MSU management policy, whether for purely performance reasons, safeguarding the Mission & Time Critical workload isn’t impacted by lower priority workloads, or for cost reasons, optimizing MSU usage for the best possible monthly WLC cost.

In conclusion, not considering and arguably not implementing z/OS VWLC related pricing mechanisms is impractical, because:

  • The VWLC and AWLC related pricing metrics deliver the lowest cost per MSU for eligible z/OS software
  • When compared with PSLC, VWLC related pricing mechanisms deliver conservative ~5% cost savings
  • A pay for what you use and therefore Sub-Capacity pricing mechanism, not the installed MSU capacity
  • If extra MSU policy management granularity is required, consider 3rd party software such as zDynaCap

Software cost savings are not just for the privileged; they’re for everyone!