Windows Admins... & Long-term capacity planning... do the two go together?

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1 Windows Admins... & Long-term capacity planning... do the two go together? Carl Stanfield EMC Australia Capacity management requires a few minutes of your day to crunch some numbers. The results are priceless as you will be able to seen how your servers are consuming available resources. For the purposes of this paper we will be looking specifically at the capacity management of exchange servers. You will be able to make purchasing decisions in an intelligent and timely manner and be able to predict the need for additional or replacement hardware before experiencing performance degradation on your existing IT infrastructure. 1. INTRODUCTION Mainframers and WinDozers... I come before you to stand behind you, to tell you something, us Windows guys know nothing about. Next Thursday, which is Good Friday, we will be collecting performance stats, for capacity planning. Implement all counters, performance is a penalty, so limit which ones you do. Deploy all your agents, we will use performance monitor instead. It makes no difference what you collect, we need to trend Exchange I/O... If you do a search on Microsoft.com for the words Capacity Planning the first response is Microsoft Office Assistance: Capacity Planning for Microsoft Office... For over 10 years long term capacity planning has been a forgotten phrase in a Windows World. It has been often traded for point solutions and stop gap measures... until now with Systems Centre well at least that s what I thought... This paper seeks to explore the science and art of estimating the space, computer hardware, software and connection infrastructure resources that will be needed over some future period of time. 2. tools. not just one!!! 2.1 Performance Monitor - isn t that a trouble shooting tool? The primary tool used in capacity planning has been Performance Monitor. Performance Monitor is typically known for its use as a troubleshooting tool, but it can also be used as a long-term trend-analysis tool. When you run Performance Monitor against an Exchange server, you affect that server's performance to some degree. If you are using the Performance Monitor as a troubleshooting tool, this typically isn't a huge problem because of the short duration of the monitoring session. But if you are going to be using Performance Monitor as a long-term capacity-planning tool, you need to seriously consider the impact it will have on your hardware. You don't want your servers to start suffering from performance problems while you're testing to see if your hardware is adequate. To prevent Performance Monitor from becoming too disruptive, you should refrain from running it directly on the hardware you're monitoring. Running Performance Monitor remotely reduces resource consumption on the servers being monitored, for everything except network bandwidth. Just like any other application, Performance Monitor requires the use of memory and CPU time. If you run it from another machine most of those resources will be taken from the machine it's running on, rather than the server you're monitoring. To limit any negative performance effects of the monitoring process, you should also limit the sampling rate. Copyright for this paper remains solely with the author. The author grants specific permission to CMG Australia to publish this paper as part of the CMGA Conference Proceedings/Journal, and electronically via the US CMG Proceedings CD ROM and CMG Australia s World Wide Web Site. Page 1 of 5

2 For a long-term collection aimed at trend analysis, I recommend using a sampling rate of once every 900 seconds (15 minutes). If the server being monitored exists across a slow WAN link, or is suffering other performance problems, you may want to cut the sampling rate to once every 1,800 seconds (30 minutes). If you plan on monitoring each server separately, you should give the log file a name that reflects the name of the server that the log applies to. On the other hand, if you plan to use the same log for all your hardware, you can give the log file a more generic name. There are convincing debates on both sides as to which method you should use. I tend to prefer to use a single log file to collect data from all the hardware, unless you need to set up different collection frequencies for some servers. For example, if sampling data every 900 seconds is acceptable for all of your servers, you can usually use a single log file. However, if you're going to sample data every 900 seconds on some servers, and every 1800 seconds on other servers, you should use multiple log files. 2.2 Microsoft Operations Manager Exchange management pack Over 30 ready-made Exchange reports ship with the Exchange management pack. When you download and expand the Exchange management pack file, you will find that the reports are contained in a separate XML file. It s then simply a case of importing the reports into MOM via the import/export feature found in the MOM Administrator Console. The Exchange reports are broken down into five categories; those categories and typical reports found within them are as follows: Health monitoring and operations. This category contains reports on availability, database sizes, disk usage, and so on. Protocol usage. Here we see reports detailing the usage of services such as the Information Store, MTA, POP3, IMAP4, and so on. Traffic analysis. These are typical top 100 style reports by size, domain and message count. Capacity planning. This category contains reports such as client logons per day, messages sent per day, and so on. Mailbox and folder sizes. Here we see useful reports such as the top 100 mailboxes and highest growth mailboxes. One useful piece of information on Exchange reports is based around the understanding of how data becomes available for reports. Basically, MOM has two databases: the main MOM database and a separate reporting database. Data is moved from the main MOM database to the separate reporting database via a SQL Data Transformation Services (DTS) job, which is performed via a scheduled task that runs once every 24 hours at 01:00. Reports are then produced against data held in the reporting database and not the main MOM database, which is deliberately kept smaller for operational efficiency reasons. A lot of the scripts to collect Exchange data do not run until after the SQL DTS job has started. This means that if you run a report first thing in the morning, it could well be missing some Exchange data that you require due to the timing of the SQL DTS job. Consequently, you can consider changing the SQL DTS job to run at 05:00 instead of 01:00 to ensure that you get all Exchange data 24 hours sooner ExBPA Management Pack The Microsoft Exchange Server Best Practices Analyzer Tool automatically examines an Exchange Server deployment and determines whether the configuration is set according to Microsoft best practices. With the proper network access, the tool can examine your Active Directory service and Exchange servers to do the following: Generate a list of issues, such as suboptimal configuration settings or unsupported or not recommended options. Judge the general health of a system. Help troubleshoot specific problems. You can run the tool against an entire deployment, against a specific server, or against a set of servers. Exchange Server Best Practices Analyzer examines servers that run Exchange 2000 Server and Exchange Server 2003, as well as servers that run Exchange Server 5.5 when they are part of a mixed-mode topology. 2.2 System Center Capacity Manager 2006 Microsoft System Center Capacity Manager 2006 guides an architect to a deployment in the most efficient Page 2 of 5

3 manner, while also allowing for what-if analyses for future planning. This has always been done via the i ve done this before and... or the Excel method (large spreadsheet with long and complicated formulas). Systems Center will allow; Collection of organisation-specific data about the end-user workload and network environment. Recommend a topology a particular configuration of servers, software, and network using pre-defined knowledge and dynamic performance modelling. Simulate the load against the proposed architecture to measure its impact on the environment. Finally Microsoft have delivered a tool that can help the rest of us define the exact impact on a proposed implementation and stop over designing systems. 3. Counters... what ones to use? Performance counter logging naturally has a big role within the world of Exchange performance and as you d expect MOM captures many other performance counters to aid understanding of your Exchange environment. Opinions vary widely regarding which counters should be monitored. Below is a list of counters I recommend using, but feel free to modify the list as you see fit. Just try to avoid using an excessive number of counters or performance may become an issue. You will also notice that some of these counters are specific to an Exchange Server. If you are running Performance Monitor from a non-exchange computer, these counters will not be available -- although, it is possible to make them accessible by installing Exchange System Manager on the computer you're using. The counters I recommend using are: Memory \ Pages / sec Memory \ Available Bytes Memory \ Committed Bytes Processor \ % Processor Time MSExchangeIS \ RPC Requests MSExchangeIS \ RPC Operations / sec PhysicalDisk \ Disk Transfers / sec PhysicalDisk \ Avg. Disk Queue Length Physical Disk \ % Disk Time SMTP Server \ Local Queue Length SMTP Server \ Messages Delivered / sec MSExchangeIS Mailbox \ Local Delivery Rate MSExchangeIS Mailbox \ Folder Opens / sec MSExchangeIS Mailbox \ Message Opens / sec Hence why MOM has specific advantages over plain old Performance Counter Logging. There are multiple counters and many different categories of performance counters that are collected by MOM that unless you are a performance monitor guru you could spend hours analysing. 4. What about a baseline??? Initial data collection should be used as a baseline for your Exchange servers (assuming that you weren't having any serious problems when the readings were taken). Your baseline values will tell you what is normal for your Exchange servers and give you something to which you can compare future measurements. Baseline values are not valid forever though. Any time a major action is performed such as installing a service pack or adding new hardware -- the next reading should be compared to the original baseline value to determine the impact of the change. After making comparison, the most recent reading should then become the new baseline value. Even if no major changes are made then every four to six months you should make your most recent reading s the new baseline, so there is always a semi-current (and realistic) baseline. Page 3 of 5

4 Spikes in activity are normal, even for a healthy server. If data sampling is every 15 minutes, it's distinctly possible that some samples will occur during big spikes of activity, and will make the server look busier than it really is. If you look at the collected data for a week and the averages seem high, the data has most likely been collected during some periods of high activity. My advice is not to worry about it. The purpose of this data collection is to look for long-term trends, to forecast future hardware needs. If your company isn't a 24-hour operation, a lack of activity at night could also skew your average values, so you might want to limit monitoring to business hours. You won't collect as much data that way, but the data you do collect will be more accurate. If you are concerned about some of the recorded values, collect data again -- but this time, sample the counters every 10 seconds. Lower sampling frequencies will do a better job of showing you spikes and lulls in activity. By exporting the Performance Monitor log data to Microsoft Excel, you can compare collected data on a week by week basis to look for long-term trends. You can even use Excel's graphing feature to display graphs of the values of individual counters. It would be unusual for a graph with a collection of weekly averages to have the sudden and long-lasting drop -- unless something major had happened with the system and additional RAM was later added to the server. A graph of weekly averages would more often look like the data that's shown after the change. It would vary from week to week, but would show a definite trend over time. It's this trend that is important to understand. If, for example, you noticed that the average Memory \ Available bytes was gradually dropping over time (even if some weeks showed an increase in average available memory), you could use that information to predict when your server's current memory might become inadequate, and use that prediction to justify additional Exchange Server hardware acquisitions. 5. Conclusion Capacity planning can help design an infrastructure with an eye on the future, by: Delivering executive-level reports on current and future performance. Assessing architectural choices for future deployments. Providing server consolidation and virtualisation migration scenarios Assessing current architectures to improve performance and availability However none of these will work unless capacity planning is implemented as an iterative process, to ensure that the appropriate resources are available when needed. With the rapid change common in many business environments, capacity management needs to put proper tools in place to remain proactive. This includes using predictive modelling and what-if scenarios to estimate appropriate levels of resources and anticipating the level of performance needed to satisfy business Page 4 of 5

5 requirements. Specific review milestones are defined and refined with the effective coordination of the service level, financial, workforce, service continuity, availability, and capacity management processes. According to the META Group, The days of capacity/performance management (C/PM) being driven by vague corporate directions and wishful line-of-business thinking are slowly coming to an end, as besieged CIOs learn to think' platform utilization and eye consolidation benefits. It is time for C/PM to seize the day and use strong processes and technical skills that can translate operational efficiencies and effectiveness into improved bottom-line performance. Leveraging the knowledge and guidance that Capacity Manager offers will provide value by driving initiatives to improve the IT infrastructure and reduce TCO. It also provides concrete data to decision-makers to drive strategic decisions. Page 5 of 5