First, to keep the offering managers and marketing team happy, I should point out that Rational Team Concert (RTC) is no longer the name but is now Engineering Workflow Management (EWM). See Renaming the IBM Continuous Engineering Portfolio for more information.
It is still true that build results, work item attachments and versioned conent are the largest contributors to EWM database size. Previously I referenced out of the box reports useful for determining which EWM namespaces occupied the most space. Since then I have documented web services and repotools reports, and Item Count Details JMX MBean that can be used to get the same information. See How many artifacts do I have in my Jazz application repository?.
Once you know which artifacts are taking up the most space, you then need to know what can and cannot be deleted. I point out some of this in the previous blog but we now have an article on the deployment wiki that goes into more detail. See Deleting data in Rational Team Concert.
A new technique for reducing the size of your EWM database is using an external content repository such as Artifactory for managing large versioned files. See Rational Team Concert: External content repositories. The article describes how to configure EWM to use an external content repository, move content in and out of it as well as serveral new JMX MBeans to monitor the size of external content repositories, size of EWM SCM components and size of the largest files.
I think the improvements since the original posting make it easier to monitor the growth of your repositories, understand what is causing it and provides better strategies for mitigating growth. As always your feedback is appreciated. If you have other techniques you find useful, please pass them on.
The following is a refresh of a previous post in 2016.
You’ve just made the decision to adopt one of the Jazz solutions from IBM. Of course, being the conscientious and proactive IT professional that you are, you want to ensure that you deploy the solution to an environment that is performant and scalable. Undoubtedly you begin scouring the IBM Knowledge Center and the latest System Requirements. You’ll find some help and guidance on Deployment and installation planning and even a reference to advanced information on the Deployment wiki. Unlike the incongruous electric vehicle charging station in a no parking zone, you are looking for definitive guidance but come away scratching your head still unsure of how many servers are needed and how big they should be.
This is a common question I am often asked, especially lately. I’ve been advising customers in this regard for several years now and thought it would be good to start capturing some of my thoughts. As much as we’d like it to be a cut and dried process, it’s not. This is an art not a science.
My aim here is to capture my thought process and some of the questions I ask and references I use to arrive at a recommendation. Additionally, I’ll add in some useful tips and best practices.
I find that the topology and sizing recommendations are similar regardless of whether the server is to be physical or virtual, on-prem or in the cloud, managed or otherwise. These impact other aspects of your deployment architecture to be sure, but generally not the number of servers to include in your deployment or their size. One exception is that managed cloud environments often start lower than the recommended target since those managing understand how to monitor the environment, look for indicators that more resources are needed and can quickly respond to increasing demands.
From the outset, let me say that no matter what recommendation I or one of my colleagues gives you, it’s only a point in time recommendation based on the limited information given, the fidelity of which will increase over time. You must monitor your Jazz solution environment. In this way you can watch for trends to know when a given server is at capacity and needs to scale by increasing system resources, changing the distribution of applications in the topology and/or adding a new server. See Deployment Monitoring for some initial guidance. Since 6.0.3, we have added capabilities to monitor Jazz applications using JMX MBeans. Enterprise monitoring is a critical practice to include in your deployment strategy.
Before we even talk about how many servers and their size, the other standard recommendation is to ensure you have a strategy for keeping the Public URI stable which maximizes your flexibility in changing your topology. We’ve also spent a lot of time deriving standard topologies based on our knowledge of the solution, functional and performance testing, and our experience with customers. Those topologies show a range in number of servers included. The departmental topology is useful for a small proof of concept or sandbox environment for developing your processes and procedures and required configuration and customization. For most production environments, a distributed enterprise topology is needed.
The tricky part is that the enterprise topology specifies a minimum of 8 servers to host just the Jazz-based applications, not counting the Reverse Proxy Server, Database Server, License Server, Directory Server or any of the servers required for non-Jazz applications (IBM or 3rd Party). For ‘large’ deployments of 1000 users or more that seems reasonable. What about smaller deployments of 100, 200, 300, etc. users? Clearly 8+ servers is overkill and will be a deterrent to standing up an environment. This is where some of the ‘art’ comes in. I find more often than not, I am recommending a topology that is some where between the department and enterprise topologies. In some cases, a federated topology is needed when a deployment has separate and independent Jazz instances but needs to provide a common view from a reporting perspective and/or for global configurations, in case of a product line strategy. The driving need for separate instances could be isolation, sizing, reduced exposure to failures, organizational boundaries, merger/acquisition, customer/supplier separation, etc.
The other part of the ‘art’ is recommending the sizing for a given server. Here I make extensive use of all the performance testing that has been done, including the following.
The CLM Sizing Strategy provides a comfortable range of concurrent users that a given Jazz application can support on a given sized server for a given workload. Should your range of users be higher or lower, your server be bigger or smaller or your workload be more or less demanding, then you can expect your range to be different or to need a different sizing. In other words, judge your sizing or expected range of users up or down based on how closely you match the test environment and workload used to produce the CLM Sizing Strategy. Concurrent use can come from direct use by the Jazz users but also 3rd party integrations as well as build systems and scripts. All such usage drives load so be sure to factor that into the sizing. There are other factors such as isolating one group of users and projects from another, that would motivate you to have separate servers even if all those users could be supported on a single server.
Should your expected number of concurrent users be beyond the range for a given application, you’ll likely need an additional application server of that type. For example, the CLM Sizing Strategy indicates a comfortable range of 400-600 concurrent users on a CCM (Engineering Workflow Management) server if just being used for work items (tracking and planning functions). If you expect to have 900 concurrent users, it’s a reasonable assumption that you’ll need two CCM servers. Scaling a Jazz application to support higher loads involves adding an additional server, which the Jazz architecture easily supports through multi-server or clustering topology patterns. Be aware though that there are some behavioral differences and limitations when working with the multi-server (not clustered) pattern. See Planning for multiple Jazz application server instances and its related topic links to get a sense of considerations to be aware of up front as you define your topology and supporting usage models. As of 184.108.40.206, application clustering is only available with the CCM application.
What are your reporting needs? document generation vs. ad hoc? frequency? volume/size?
Most of these questions primarily allow me to get a sense of what applications are needed and what could contribute to load on the servers. This helps me determine whether the sizing guidance from the previously mentioned performance reports need to be judged higher or lower and how many servers to recommend. Other uses are to determine if some optimization strategies are needed.
As you answer these questions, document them and revisit them periodically to determine if the original assumptions, that led to a given recommended topology and size, have changed and thus necessitate a change in the deployment architecture. Validate them too with a cohesive monitoring strategy to determine if the environment usage is growing slower/faster than expected or detect if a server is nearing capacity. Another good best practice is to create a suite of tests to establish a baseline of response times for common day to day scenarios from each primary location. As you make changes in the environment, e.g. server hardware, memory or cores, software versions, network optimizations, etc., rerun the tests to check the effect of the changes. How you construct the tests can be as simple as a manual run of a scenario and a tool to monitor and measure network activity (e.g. Firebug). Alternatively, you can automate the tests using a performance testing tool. Our performance testing team has begun to capture their practices and strategies in a series of articles starting with Creating a performance simulation for Rational Team Concert using Rational Performance Tester.
In closing, the kind of guidance I’ve talked about often comes out in the context of a larger discussion which looks at the technical deployment architecture in a more wholistic perspective, taking into account several of the non-functional requirements for a deployment. This discussion is typically in the form of a Deployment Workshop and covers many of the deployment best practices captured on the Deployment wiki. These non-functional requirements can impact your topology and deployment strategy. Take advantage of the resources on the wiki or engage IBM to conduct one of these workshops.
As a deployment architect when advising customers on their topology, I’m often asked about the supported options for reverse proxies and load balancing. Further, some customers ask about using DNS aliasing over a Reverse Proxy, which is supported but not a best practice.
While some of these details can be found in the Knowledge Center and deloyment wiki, we’ve not had a central article listing options with any comparisons. My colleagues in IBM Support have recently published an article with these details here: Reverse Proxies and Load Balancers in CLM Deployment.
In Resource-intensive scenarios that can degrade CLM application performance I describe how certain IBM Collaborative Lifecycle Management (CLM) application scenarios can be resource-intensive and known to degrade system performance at times. As I’ve intereracted with customers on their deployments and performance concerns, it is apparent that they are getting more and more creative in building custom automation scripts/utilities using our APIs. At times, these custom utilities have generated significant load on the system.
As a best practice, we now recommend that customers evaluate their custom utilities and determine if any are candidates to be resource-intensive. For those that are, they should be modified and registered as resource-intensive with appropriate start and stop scenario markers included in the code. Until recently, all we could provide to help do this was some code snippets.
Thanks to my colleagues Ralph Schoon, Dinesh Kumar and Shubjit Naik, we now have documented guidance and sample code to help you do this. Have a look at Register Custom Scripts As a Resource Intensive Scenario. Ralph also gives some additional detail behind the motivation for the custom scenario registration in his blog post.
Once registered, you will now be able to track their occurrence in the appropriate application log. If you’ve implemented enterprise application monitoring, you can track for available JMX MBeans as described in CLM Monitoring.
One element of sizing the servers for the IBM Continuous Engineering (CE) solution is the current and projected data scale (along with data shape, user scale and workload). There are also recommended artifacts limits to keep an application performing well, such as 200K artifacts per DNG project area (as of v6.0.5 and noted here).
Whether you are trying to project future growth based on current sizing or ensure you are staying withing recommended limits, it is useful to know how many artifacts currently exist in a repository (or other “container” such as a project area). Each application provides different means of getting this information.
DOORS Next Generation (DNG)
Vaughn Rokosz has written a very good article on the impact of data shape on DNG performance. He provides several SQL and SPARQL queries to monitor artifact counts. I won’t repeat them here but go to the link to minimally get the queries for total number of artifacts and versions in the repository and artifacts in the project areas.
Rational Team Concert (RTC), Rational Quality Manager (RQM) and Rational Model Manager (RMM)
Since these applications share a common storage service, they have similar means to get to the artifact counts. As a Jazz Admin you can run a repotools command or a web service.
for <context>, use ccm, qm or am for Change Configuration Management, Quality Management or Architecture Management applications.
Note that both of these options can take some time to execute so be aware of possible load put on the server. I suggest running them during lighter load times. You can first run in a test environment with production like data to get a sense of timing and load.
Sample CCM artifact counts output
Sample QM artifact counts output
Starting with v6.0.3, administrators can monitor Jazz application metrics through the use of JMX MBeans. One of the MBeans is Item Count Details which contains similar information as provided by the listItemStats repotools command and IDBTableSizeHttpService web service. The Item Count Details MBean, once enabled can be viewed from RepoDebug or an enterprise monitoring tool capable of receiving published JMX inputs. This is the preferred method as you can capture that data over time, see trends, set alerts and thresholds and correlate with other monitored data.
I recently published a blog post on jazz.net regarding our serviceability strategy and use of JMX MBeans to monitor Jazz Applications. If you’ve heard me speak on this topic, you know that I believe that having an monitoring strategy is a best practice and essentially imperative for any deployment involving our global configuration management capability. I would even extend that to deployment of RTC clustering as well.
Earlier this year, Kathryn Fryer and I formed a workgroup to share experiences we’ve had with customers adopting the IBM CLM configuration management solution. The purpose being to elicit our shared recommended practices and guidance. The workgroup consisted of representatives from Services, Support, Development, Test, Enablement and Product Management.
When forming your Configuration Management plan we recommend it consider the following key topics:
End to End Process Flow (context for use of configuration management)
Change Management (including DNG change sets)
Reviews and Approvals
Traceability, Link Validity and impact analysis
Naming, Tagging, Custom Attribute Conventions
Roles and Permissions
Configuration aware Reporting
Integrations (including non-CLM)
Our aim is to create guidance that encompasses each of these topic areas to aid you in creation of your configuration management plan.
The first such guidance is now available on jazz.net.
Our focus has been on general adoption guidance along with component and stream strategies (both are critical at the outset and go hand in hand). Next focus areas are yet to be determined but could include finishing out the stream strategies (a couple more patterns remain) baselining strategy and change management.
We value your feedback on the guidance to date and input on areas to focus on next.
If you are at the IBM Watson IoT: Continuous Engineering Summit 2017 this week in New Orleans, be sure to say hello. Check out the talk I have with Ian Zimmerman on Friday at 2:30pm (Azalea 1): CM05 – Adopting Configuration Management: What You Need to Know!