ehealth Element and Poller Management Guide

Transcription

1 ehealth Element and Poller Management Guide MN-EHADMPM-001 October 2006

2 This documentation (the "Documentation") and related computer software program (the "Software") (hereinafter collectively referred to as the "Product") is for the end user's informational purposes only and is subject to change or withdrawal by CA at any time. This Product may not be copied, transferred, reproduced, disclosed, modified or duplicated, in whole or in part, without the prior written consent of CA. This Product is confidential and proprietary information of CA and protected by the copyright laws of the United States and international treaties. Notwithstanding the foregoing, licensed users may print a reasonable number of copies of the Documentation for their own internal use, and may make one copy of the Software as reasonably required for back-up and disaster recovery purposes, provided that all CA copyright notices and legends are affixed to each reproduced copy. Only authorized employees, consultants, or agents of the user who are bound by the provisions of the license for the Software are permitted to have access to such copies. The right to print copies of the Documentation and to make a copy of the Software is limited to the period during which the license for the Product remains in full force and effect. Should the license terminate for any reason, it shall be the user's responsibility to certify in writing to CA that all copies and partial copies of the Product have been returned to CA or destroyed. EXCEPT AS OTHERWISE STATED IN THE APPLICABLE LICENSE AGREEMENT, TO THE EXTENT PERMITTED BY APPLICABLE LAW, CA PROVIDES THIS PRODUCT "AS IS" WITHOUT WARRANTY OF ANY KIND, INCLUDING WITHOUT LIMITATION, ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NONINFRINGEMENT. IN NO EVENT WILL CA BE LIABLE TO THE END USER OR ANY THIRD PARTY FOR ANY LOSS OR DAMAGE, DIRECT OR INDIRECT, FROM THE USE OF THIS PRODUCT, INCLUDING WITHOUT LIMITATION, LOST PROFITS, BUSINESS INTERRUPTION, GOODWILL, OR LOST DATA, EVEN IF CA IS EXPRESSLY ADVISED OF SUCH LOSS OR DAMAGE. The use of this Product and any product referenced in the Documentation is governed by the end user's applicable license agreement. The manufacturer of this Product is CA. This Product is provided with "Restricted Rights." Use, duplication or disclosure by the United States Government is subject to the restrictions set forth in FAR Sections , , and (c)(1) - (2) and DFARS Section (c)(1)(ii), as applicable, or their successors. All trademarks, trade names, service marks, and logos referenced herein belong to their respective companies. Copyright 2006 CA. All rights reserved.

3 Table of Contents Preface 5 Audience About This Guide Reading Path Revision Information Documentation Conventions Technical Support Chapter 1 Managing the Data Collection Process 7 Understanding the Polling Process: Important Concepts After You Save Discover Results Controlling the Polling Rates and Intervals Stopping and Starting the Poller Changing the Statistics Poll Rates Changing the Conversation Poll Rate Viewing the Poller Configuration Using OneClickEH Using the ehealth Console Managing Poller License Consumption Freeing Licenses Using DCI to Modify Element Information Your Resource Management Roadmap Chapter 2 Resolving Polling Errors 13 OneClickEH Status Summary Understanding the Cause of Common Polling Errors Identifying Polling Problems Investigating the Problems Taking Action

4 4 Table of Contents Chapter 3 Modifying Your Element Configuration 21 Updating Element Properties Agent Type SNMP Index Interface Speed Element Values (Discovered Information) Specifying User Strings to Use as a Filter in OneClickEH Making Element Names More Intuitive Element Names Aliases Excluding an Element from Live Exceptions Monitoring Recording Statistics Data for an Element Tracking Changes to the Poller Configuration Monitoring Administration Changes Chapter 4 Adding New Elements to Your Configuration 29 Adding a Statistics Element Creating a Modem Pool Element Adding a Permanent Virtual Circuit Element for a Frame Relay Element Managing Alternate Latency Understanding Alternate Latency Collection Configuring the Alternate Latency Ping Process Disabling Alternate Latency Data Collection Chapter 5 Organizing Your Elements by Grouping 35 The Purpose of Grouping Creating Groups and Group Lists Controlling Access to Groups and Group Lists Editing and Copying Groups and Group Lists Deleting Groups and Group Lists of Elements Focusing ehealth Console Administration on One Group.. 40 Chapter 6 Troubleshooting Common Problems 43 ehealth Misses a Scheduled Poll Unable to Report on Router Interface Elements ehealth Reports the Speed of Elements as Zero Cannot Save Data for an Element in the Database Index 45 ehealth Element and Polling Management Guide

5 Preface This guide describes the ehealth element and poller management process collecting, modifying, and maintaining data on the health of the resources that ehealth is monitoring. Element and poller management is one of several primary tasks that an ehealth administrator performs. This guide supports ehealth Release 6.0 and later. Audience This guide is intended for anyone who must perform element and poller management or is responsible for managing one or more aspects of this administrative function. Before you use this guide, you should become familiar with network terminology, general ehealth concepts, and the resource discovery process. About This Guide This section describes the reading path that you should follow, as well as the revision history of this guide. It also includes the documentation conventions used in this guide. Reading Path Prior to reading this guide, you should review the Introduction to ehealth guide and the ehealth Administration Overview Guide. You can refer to the ehealth Resource Discovery Guide for detailed information about the process that ehealth uses to find the resources to monitor. These guides are available in PDF format in the ehealth Web Help and on the Support web site. Revision Information This is the first release of this guide. 5

6 6 Preface Documentation Conventions Table 1 lists the conventions used in this document. Table 1. Documentation Conventions Convention File or Directory Name code emphasis enter Name New Term Variable NOTE Description Text that refers to file or directory names. Text that refers to system, code, or operating system command lines. Text that refers to guide titles or text that is emphasized. Text that you must type exactly as shown. Text that refers to menus, fields in dialogs, or keyboard keys. Text that refers to a new term, that is, one that is being introduced. Text that refers to variable values that you substitute. A sequence of menus or menu options. For example, File Exit means Choose Exit from the File menu. Important information, tips, or other noteworthy details. CAUTION WARNING Information that helps you avoid data corruption or system failures. Information that helps you avoid personal physical danger. Technical Support If you have a Support Contract ID and password, you can access our Support Express knowledgebase at the following URL: If you have a software maintenance contract, you can obtain assistance with ehealth. For online technical assistance and a complete list of primary service hours and telephone numbers, contact Technical Support at

7 1 Managing the Data Collection Process Managing element data that ehealth collects on your resources is a critical administration task. Over time, your infrastructure changes, so it is important to proactively maintain it to ensure that ehealth can continue to collect data on the health of your resources. This chapter begins by describing the important concepts associated with managing the process of data collection (the polling process), and explains how to control the collection rate. It follows with procedures for viewing your element data and managing your poller license consumption. Understanding the Polling Process: Important Concepts To monitor and manage the performance of networks, systems, and applications, the ehealth software locates resources, or elements, within your infrastructure through a process referred to as discovery. To find the resources, ehealth uses Simple Network Management Protocol (SNMP) agents to search for the IP addresses that you specify. It then obtains information from the management information base (MIB) of each device and creates elements based on that data. After You Save Discover Results When you save the discover process results, ehealth stores the element information in its database and its poller configuration. The ehealth poller automatically collects performance and availability statistics data from the network, system, and applications elements in the ehealth poller configuration through a process referred to as polling. The poller configuration defines the information that is specific to each element such as the name, any configuration information that ehealth obtained during discovery, the polling rate (the frequency with which ehealth polls the element), and the agent type (the type of element that ehealth discovered). While discover can keep the majority of your poller configuration up-to-date automatically, the discover process works most effectively when you maintain your configuration by correcting polling problems, deleting resources that have been removed from the infrastructure, and adding new ones. When resources change so drastically that discover cannot match any of their attributes to existing elements, you need to manually update the element information to prevent or resolve discover errors and duplicate elements. If you do not actively manage and maintain your poller configuration, ehealth will not be able to successfully collect data on your resources. Managing Discovered Elements ehealth provides two administrative interfaces that you can use to manage the poller and your elements: the ehealth console and the OneClick for ehealth console (OneClickEH). Not all functions are available through both interfaces; some are only available in one. This document provides guidelines for performing each task. 7

8 8 Chapter 1 Managing the Data Collection Process Controlling the Polling Rates and Intervals The ehealth poller runs continuously to regularly collect data from elements. You can stop the poller to troubleshoot problems, and you can control how it runs. If you do not want to collect data all day or every day of the week, you can configure the poller to run only during certain hours of the day and also control the collection intervals. Stopping and Starting the Poller Using the Poller Controls option in the Setup menu of the ehealth console, you can turn the poller on or off for all of your resources, set it to run continuously, or set it to run between two specific times of the day. You can also control the amount of data that you collect by customizing the polling interval the rate at which ehealth collects statistics data and conversation data. When you turn off polling, you are turning off the statistics, import, and conversation pollers, so ehealth does not poll any elements. As a result, reports show a gap during periods when the poller is off. Changing the Statistics Poll Rates By default, ehealth polls all elements at the Normal rate (every 5 minutes). With the exception of alternate latency elements, the statistics poller can also poll statistics elements at two other rates: Slow (every 30 minutes) and Fast (every minute). When ehealth polls an element at the Slow or Normal rates, it saves the data in the database during each poll. For those elements that are polling at the Fast rate, ehealth collects one-minute samples and saves the aggregate 5-minute sample (the normal poll interval) as a single sample in the database. For individual elements, you can also set a fourth rate, Fast Store, to collect data with a higher granularity. When you poll elements at the Fast Store rate, ehealth collects data at the Fast rate and stores the samples in the database without aggregating them. For example, if you have set the Fast poll interval to 30 seconds (using the Poller Controls dialog), ehealth collects 30-second samples for those elements and saves the individual samples every 5 minutes (at the Normal poll interval) without aggregating the data. To set the poll rate for individual elements, use the Edit Element window in OneClickEH. To set global controls that impact all elements that you are polling, use the Poller Controls dialog in the ehealth console. Modifying the Polling Interval. You can use the Poller Controls dialog to change the Fast rate to 30 seconds or 2.5 minutes. You can change the Normal rate to 10, 15, or 30 minutes, and change the Slow rate to 60 minutes. By increasing the Normal and Slow polling intervals, your database does not grow as quickly, but the data in the reports has less granularity. As a result, you might not observe peaks because ehealth averages them over a longer sample time. If poll intervals are too long or you have a complex polling environment, the devices may lose data or discard it before ehealth can collect it from them. As your ehealth element configuration becomes larger, you may need to tune your statistics poller to ensure that the poller operates more efficiently, reduce the SNMP polling impact on shared system resources, and allow the ehealth installation to maximize its element configuration size. For instructions, refer to the Tuning the ehealth Statistics Poller White Paper, which is available on the Support web site. For additional guidelines on changing the polling interval, refer to Guidelines for Changing to the Fast and Fast Store Rates on page 17.

9 Viewing the Poller Configuration 9 Changing the Conversation Poll Rate The default polling interval for conversation data (which applies to data collected by Traffic Accountant) is 30 minutes, but you can set it to 15, 45, or 60 minutes. The polling interval is longer than that for statistics data because ehealth polls each Traffic Accountant probe to collect data on every conversation that the probe detected, which can result in a tremendous amount of data being collected at each poll. Probe memory can vary and determines the amount of conversation data that ehealth collects from the probe. Use a polling interval that allows you to retrieve data from the probe before it resets counters or drops data. The number of elements in your database and the amount of disk space available for the database might require you to use a polling interval that is longer than the default. 1 Viewing the Poller Configuration To view all elements that you are monitoring and their associated configuration information, you can use the ehealth console or OneClickEH. Each interface provides unique capabilities. Using OneClickEH To view and modify the poller configuration through OneClickEH, click Find Elements in the Managed Resources folder and select the Element Chooser tab. Table filters Filtering the Table Display By default, OneClickEH immediately shows all of your elements in the table. If you specify matching criteria in the Filter table by field at the top of the console screen, it filters the list as you type. If you have a very large configuration, OneClickEH can require several minutes to show the entire list. To filter your element list before OneClickEH displays the entire element configuration, you can disable these features. To modify the matching criteria before OneClickEH displays all elements: 1. Select Tools Options Advanced at the top of the console to display the Advanced Settings dialog. 2. Deselect Show all elements immediately when displaying element tables. 3. Optionally, if you want ehealth to allow you to finish specifying all matching criteria before it filters the list, also deselect Filter element tables as you specify the filtering criteria. 4. Click OK to close the Advanced Settings dialog. 5. Select the Element Chooser tab. 6. Specify matching criteria in the Filter table by field; then click Go to complete the operation.

10 10 Chapter 1 Managing the Data Collection Process Searching for Elements Additionally, you can filter your element search based on a specific name, alias, or IP address. You can select Name or Alias from the list on the Element Chooser page and specify a portion of the element s name using wildcards (for example, *boston*). You can also specify the digits of one or more of IP address octets in the IP Address field. You can use the * symbol as a wildcard to search for all numbers within the range of 0-250, but you cannot use the wildcard to search for a single digit. All sample formats shown in the following table are valid: Type Examples Range 111.* 111.*.11.* * * * *-30 List ,15,17.* 20,27,32.11.*.11 You can also exclude the element s subcomponents from your search. After OneClickEH finds the elements that match your search criteria, it displays the properties in the element table. In each view, you can sort any column to quickly find elements of particular interest to you. You can move, reorder, and resize the columns. If you want to save the data, you can copy, export, or print it. Using the ehealth Console To view and modify the poller configuration through the ehealth console, select Setup Poller Configuration, as shown in Figure 1. By default, the dialog displays all elements in your configuration sorted alphabetically by name. Using various options, you can reorder and filter the list to show specific elements, and manage all of your element types. If you enable the global setting in the Options dialog to display alias names, the poller configuration shows aliases in the list. To find an element, enter a string in the Search for Name field. You can use wildcards, such as an asterisk (*) to match zero or Figure 1. Poller Configuration Dialog more characters or a question mark (?) to match any single character. If you enter a string without any wildcards, the filter displays the elements that contain that string anywhere in the name. If the Search for Name field is empty, the filter displays all elements.

11 Managing Poller License Consumption 11 Saving the Poller Configuration Information To manage the poller configuration, you can save some or all of the information that appears in the Poller Configuration dialog by outputting it to a file. The resulting ASCII file can be useful for inventory checking and for reviewing the elements that you are monitoring. For example, you could use it to devise a list of alias names. The Save List To File option (located in the lower right corner of the dialog) saves all configuration data that is currently displayed in the dialog and stores it in an ASCII file named poller.cfg.log in the /ehealth/log directory. If the file already exists, ehealth overwrites it with the new information. To simply output a list of element names that exist in your poller configuration, you can run the nhlistelements command. 1 Managing Poller License Consumption You can discover any number of elements; however, ehealth will only poll elements that have a poller license. ehealth uses poller licenses to control the number of elements that you can poll. Although most elements only consume one license, it is important to track the number of licenses that ehealth requires for all of the elements in your poller configuration. You can manage your poller license consumption from the OneClickEH Status Summary window that appears immediately after you log in to your ehealth system. From that window, you can identify the number of poller licenses that are available for use, the total number of licenses that you have, and the total number that you need to poll all of your elements. For instructions on purchasing additional licenses, refer to the Technical Support web site. Freeing Licenses If you do not need to monitor all of your elements, you can free some licenses by turning off polling for them or deleting them. When you turn off polling for an element, it remains in the database, but it does not require a license because ehealth is no longer collecting data for it. These procedures are discussed in detail in Disabling Polling on page 17. In some cases, two elements may share a license. To identify those elements that are the primary consumers of a license, and those that share a license with another element, use the nhlistelementlicenses command. To free a license for use by another element, you need to delete or disable all primary elements that share the same license. The nhlistelementlicenses command also identifies those elements that do not need a license and those that are not consuming a license. Using DCI to Modify Element Information If you have a network management system (NMS) or other source at your site that collects configuration information and data for your resources, you can use the ehealth DataSync application programming interface to import element information. When you need to modify element configuration information in the ehealth database, you can export the information to a Database Configuration Information (DCI) file, modify the information, then import it into the ehealth database. To use DataSync, you must be comfortable creating programs, scripts, and files that use complex syntax and have a working knowledge of ehealth. For detailed instructions, refer to the ehealth Integration Guide.

12 12 Chapter 1 Managing the Data Collection Process Your Resource Management Roadmap This chapter provides an overview of the ehealth polling process and how to access the controls. Managing the process of collecting, modifying, and maintaining the data is a critical administrative function that involves several primary tasks (outlined in Table 1) that are discussed in the remaining chapters. Table 1. Resource Management Tasks Task Description Chapter Resolving Polling Errors Updating Element Information Adding New Elements Organizing Elements Use the OneClickEH Statistics Polling Management interface to identify and resolve polling problems to ensure that ehealth can continue to collect data. Use the ehealth console Poller Configuration dialog and OneClickEH to manually modify element properties and make element names easily recognizable. Use the ehealth console Poller Configuration dialog to manually add elements that discover is unable to find. Use the OneClickEH Managed Resources interface to organize related elements into groups for easier reporting and management. Chapter 2 Chapter 3 Chapter 4 Chapter 5

13 2 Resolving Polling Errors To ensure that ehealth can continue to collect data on your resources, it is important to monitor polling, identify errors, and quickly resolve any polling problems that occur. This chapter provides you with guidelines for using the OneClickEH Statistics Polling Management interface to perform those tasks. OneClickEH Status Summary The OneClickEH Status Summary window (Figure 2) summarizes all polling activity that takes place on your ehealth system and updates it every minute. If your web user account has permission to manage statistics polling, you can click All Errors to drill down to the Statistics Polling Management interface from this window and review polling problems and errors. To resolve an error, you can right-click any element and select an option from the pop-up menu. Figure 2. ehealth Status Summary 13

14 14 Chapter 2 Resolving Polling Errors Understanding the Cause of Common Polling Errors After successfully discovering your elements, you could encounter some common polling problems such as those described in Table 2. Errors can result from temporary or prolonged network delays or connection problems, element index shifts, and traffic congestion. You can also receive errors if you are polling devices that have not been certified for use with ehealth. Table 2. Typical Polling Errors (Page 1 of 2) Polling Error Device Exceeded Allowable Timeouts Received Large Delta Error No Response (to SNMP) Received an SNMP Error Description When devices with multiple elements such as routers or servers do not respond to SNMP requests, the information that the poller collects is incomplete. In addition, if those elements are consistently unresponsive, the performance of the poller is negatively impacted. To ensure that polled data is accurate and to limit the amount of time that ehealth spends polling one device, ehealth tracks the number of SNMP request timeouts. If it exceeds the value of NH_SNMP_DEVICE_TIMEOUTS, it stops polling any elements associated with that device and proceeds to poll the next device. Resolution: If the device has not responded for one or two polling cycles, the problem could be a temporary one. If you wait another polling cycle or two, the problem may resolve itself. If the device has never responded to polls, the element information could be incorrect or the SNMP agent could be down. Contact the device owner to investigate problems. A counter wrap occurs when one or more MIB variables reaches its maximum value, resets to zero, and begins counting again within one polling cycle. When the delta, which is the difference between the counter values for the last poll and the current poll, reaches or exceeds 50% of its maximum value, ehealth identifies this as a large delta error. It discards the data for that element for that poll because the counter wrap can cause unusual results in reports and performance monitoring. Resolution: Most often, delta errors occur with high-speed links or devices. Their MIB counters increment so quickly that they can wrap within the normal five-minute polling interval. Use OneClickEH to change the statistics polling rate by right-clicking and selecting Fast Poll to Resolve Large Deltas. If the index shifted as a result of a reboot or other configuration change, right-click and select Rediscover or select Rediscover with Rules to rediscover the device and update the poller configuration. If the error persists, verify that the device is certified for use with ehealth. Search for the device at If the polled device does not respond to an ehealth poll within a specified amount of time, ehealth generates an error and does not collect any data for that element for that poll interval. Resolution: If the agent is running, the problem may be due to temporary network delays. Wait a few poll cycles to see if the error persists. If the element has never responded to SNMP requests, increase the time that ehealth waits for an SNMP response and the number of times that it retries by modifying the NH_SNMP_TIMEOUT and the NH_SNMP_RETRIES environment variables. To prevent wasteful increases in the overall poll cycle time, increment the value by one second and then wait to observe the impact. If rediscovery is not successful, refer to the Poller Tuning Guide that is available on the Support web site. If a device was unable to provide an object identifier (OID) in response to an SNMP request from ehealth, ehealth generates a generic SNMP error. This can occur when polling information is out-of-date because the element had an index shift or the device has not been certified by CA. Resolution: Using OneClickEH, right-click and select Rediscover. If the SNMP error persists, ensure that the device responds to SNMP V1 get commands, and then verify that the device is certified for use with ehealth. Search for the device at

15 Identifying Polling Problems 15 Table 2. Typical Polling Errors (Page 2 of 2) Polling Error Description 1 No Response to ping ehealth pings each IP address before it sends an SNMP request. If the device does not respond to the ping request, ehealth considers it to be a missed poll and does not collect SNMP data from the device. Ping failures can occur because of network connection problems that either prevent the ping request from reaching the polled device or prevent the ping response from reaching the ehealth system. Ping failures also occur if the device is off. Also, when traffic on the network is congested, routers and switches may discard ping requests in favor of higher-priority traffic. Resolution: If the ping failure is local to one or more devices, use OneClickEH to ping it. Right-click the element and select Ping from Server. If it does not respond, it may be off. If you determine that the device has been removed from the network, delete or retire the element by right-clicking it. If ping errors are occurring for many elements in your configuration and you have confirmed that the cause is not due to temporary network conditions, you can increase the value of the NH_POLL_PING_TIMEOUT environment variable. If you have network restrictions that would always prevent a successful ping, you can disable the ping operation with each poll using the NH_POLL_PING_DISABLED environment variable. This will allow ehealth to gather SNMP responses, but calculate reachability based on SNMP responses rather than true device reachability using ping. Identifying Polling Problems To access all ehealth elements that have reported polling errors during the last Normal polling period, you can use the OneClickEH Statistics Polling Management interface. The element table displays the name and properties of every element that has an error, and the time period for which ehealth has not collected data, as shown in Figure 3. You can easily sort the data and reorder the columns to find specific problems. Figure 3. Element Table Investigating the Problems If your web user account has permission to manage elements, you can right-click any element (except those that are remotely polled) to access the pop-up menu, as shown in Figure 4. To investigate why ehealth was unable to poll an element, as an initial step, you can ping the element from the server to confirm that the element exists and is active within your infrastructure, and that the network connection from ehealth to the device is working. If the element responds to ping, ehealth should be able to collect data from it the next time that a poll occurs. Ping the element Figure 4. Element Actions

16 16 Chapter 2 Resolving Polling Errors If the element does not respond to ping, you can drill down to an At-a-Glance report or a Trend report to troubleshoot problems. You could also generate an Element Configuration report to review the element s configuration details and identify its relationships, or associations, to other elements. If an element repeatedly does not respond to ping, but you know that it exists, modify the number of times that ehealth will attempt to retry polling and also change the timeout rate. Double-click the element in the table. In the Edit Element window, select Polling, specify the timeout and retries values, and click OK. Taking Action If you are not able to resume polling for the element by manually pinging it, take one of the actions described in Table 3 to resolve the problem. These methods are described in detail in the following sections. Table 3. Element Actions Available Element Action Change the polling rate. Disable polling for the element. Modify the community string. Rediscover. Delete the element. Retire an element. Result Enable ehealth to collect data less frequently to accommodate a device that is experiencing heavy traffic. Stop collecting data from the element temporarily, or allow another element to use the poller license. Update the SNMP password that ehealth uses to control read-write access to data. Update the element in your poller configuration. Stop polling the element and stop reporting on it. Stop polling the element, but continue to include element data in reports. Any changes that you make to statistics or conversation elements take effect during the next poll. The poller does not restart; the changes take effect without interrupting the polling cycle. The following sections provide guidelines. For detailed instructions, refer to the OneClickEH Web Help. Changing the Polling Rate By default, ehealth assigns the Normal polling rate to newly discovered statistics elements. It polls elements every 5 minutes and saves the data to the database during the poll. This is the rate that you should typically use to collect data from statistics elements, but ehealth can also poll at these three other rates: Rate Slow Fast Fast Store Data Collection Process ehealth polls elements every 30 minutes and saves the data in the database during the poll. You can change the default interval to 60 minutes. ehealth aggregates the data from five 1-minute polls into one 5-minute average sample before saving it to the database. This process ensures that the data samples are consistent. You can change the default interval to 30 seconds or 2.5 minutes. ehealth collects data at the Fast rate and stores the samples in the database without aggregating them. If you poll parent elements at the Fast Store rate, you must change the poll rate of each individual child element to Fast Store. Otherwise, ehealth polls their children at the Fast rate and does not store the data.

17 Identifying Polling Problems 17 If an element that is being polled at the Fast rate consistently shows missed polls in the OneClickEH Status Summary window, the element agent might not be able to respond to the SNMP polls during the fast interval. To enable the agent to respond, you should assign the Normal rate to the element. In contrast, the Slow polling rate allows you to poll elements that require even more time to respond, as well as to poll those elements that you want to poll less frequently because you do not expect their utilization rates to change. This rate is also effective for elements that are not located close to the ehealth system and cannot respond during the Normal poll interval. 1 Guidelines for Changing to the Fast and Fast Store Rates. To resolve a polling problem, OneClickEH allows you to quickly change any element to the Fast or Fast Store rate. Double-click the element name and select the Polling tab in the Edit Element window; then select a poll rate. Typically, you should only use the Fast rate to collect data more frequently from high-speed devices that do not support 64-bit counters, such as FDDI or ATM interfaces. High-speed element agents collect a significant amount of data during a Normal (five-minute) polling period. If a high-speed interface indicates significantly less volume than you expect, or it generates a large delta error, polling it at the Fast rate can ensure that ehealth will not miss data. The Fast rate is also effective for collecting data from modems or ISDN connections that have short-duration connections. NOTE You can poll alternate latency elements at the Normal rate only. To ensure that fast-polled data samples are consistent, ehealth aggregates the data from five 1-minute polls into one 5-minute average sample before saving it to the database. When it polls at the Fast Store rate, ehealth saves the 1-minute samples and does not aggregate them. Therefore, when you use the Fast or Fast Store rate, your system performance requirements increase. Depending on the size of your ehealth system, if you poll too many elements at the Fast rate, the poll might not finish before the next Fast poll is scheduled to begin. To determine the equivalent polling load, multiply the number of Fast-polled elements by the ratio of Normal poll rate to Fast poll rate, and add that number to your total number of elements. For example, if you have 5000 elements, and 200 are polled at the Fast rate, the poller is actually performing (200x5)=5800 polls during a Normal 5-minute polling interval. Disabling Polling Using OneClickEH, you can easily disable polling for one or more elements by right-clicking them in the element table. When you disable polling for an element, it remains in the database and in the poller configuration, but ehealth no longer collects data for it. You may want to disable an element to exclude it from reports temporarily or permanently: If you are unable to determine why an element is generating an error after being polled, you should disable polling for it while you try to resolve the error. If you attempt to poll an element that is not certified, it will generate a Received an SNMP Error or Received Large Delta Error. While your request for certification is being processed, you should disable polling for the element to prevent subsequent errors. If you disable polling for a router or a system, keep in mind that ehealth also disables polling for all elements that belong to that router or system. However, it continues to poll any router or system interfaces that record detail data unless you specifically disable polling for those interfaces.

18 18 Chapter 2 Resolving Polling Errors Redistributing Polling Licenses. You can only poll elements for which you have available poller licenses. If you do not need to poll one or more elements, you can free the licenses by disabling polling for the elements. When you disable an element temporarily, it remains in the database, but it does not consume a license. In some cases, you may just want to free the license temporarily for another element. To free a license for use by another element: 1. Right-click the element in the OneClickEH table and select Disable Polling. 2. Double-click the element that needs the license. 3. In the Edit Element window, select the Polling tab. 4. Select Yes from the Polling Enabled list to enable polling. ehealth automatically assigns the free license to that element and begins polling it. Changing the Community String The community string is used by administrators to grant read and write access to various device MIBs. ehealth typically uses a read-only community string to poll devices. If you change the read-write community string or the read-only community string of a device, you must change the community strings that ehealth uses for the element that represents the device. Otherwise, ehealth cannot poll the device. If your web user account has permission to manage community strings from the OneClickEH interface, you can easily change both the read-write and read-only community strings for an element that you are monitoring. To quickly change the read-write community string for an element, right-click the element name and select Modify Read-Write Community. Specify a maximum of 64 single-byte or 32 double-byte characters using the letters A through Z and a through z, backslashes, and the numbers 0 through 9. Do not use the word All, spaces, and commas. If you include a backslash (\) in a community string at the command line on a UNIX system, you must supply an additional backslash as an escape character. On a Windows system, do not supply the extra backslash escape character. To change both the read-write and the read-only community strings for an element, double-click it to display the Edit Element window; then select the General tab. Specify a read-write community string for SNMP Gets and Sets, which includes creating, modifying, or deleting MIB monitoring rows, and automatic licensing; then specify a read-only community string for SNMP Get requests. Rediscovering an Element If an element generates a Received Large Delta Error, the index may have shifted as a result of a reboot or other configuration change. To resolve the problem, you can right-click the device name in the OneClickEH element table and select Rediscover to try to update the poller configuration. (If you are using DCI rules files to filter your discoveries, you can select Rediscover with Rules to specify the rules for your rediscovery). Large delta errors may also occur if you have not applied the latest device certification patch. Once you have applied it, you need to rediscover using the same method. When you rediscover an element using OneClickEH to correct polling problems, OneClickEH runs the same discover process that is available from the ehealth console based on some default guidelines for determining the type of discovery to run, and the level of changes to make. For those devices that may have more than one element, it rediscovers the entire device, not just the one element that is having polling problems. As a best practice, always review the Discover log carefully before saving the results to confirm the changes that OneClickEH identifies.

19 Identifying Polling Problems 19 Changing the Retries and Timeout Rate If you receive a No Response (to SNMP) error for an element that has never responded to SNMP requests, you can increase the time that ehealth waits for an SNMP response by double-click the element in the OneClickEH table. In the Edit Element window, select Polling, specify the poll timeout value, and click OK. By default, ehealth waits four seconds ( microseconds) before timing out, based on the value of the NH_SNMP_TIMEOUT environment variable. To prevent wasteful increases in the overall poll cycle time, increment the value by one second and then wait to observe the impact. By default, ehealth attempts to retry polling three times (based on the NH_SNMP_RETRIES environment variable setting) before skipping the element and recording the poll as a missed poll. You can specify a value in the Poll Retries field to increase or decrease the number of times that ehealth will attempt to retry polling an element before giving up on the poll. 1 Removing Elements That You Do Not Want to Monitor Over time, you may remove resources from the infrastructure or determine that you no longer want to monitor them. If you continue to poll elements that do not exist, ehealth will generate No Response to Ping polling errors, and future discoveries will list those resources as Missing Elements in the discover log. To keep your poller configuration up-to-date, and prevent ehealth from polling these elements, you must delete or retire them from your poller configuration. Deleting an element is a permanent action. You will not be able to resume polling for that element in the future, and ehealth will no longer include that element in its reports. When you retire an element, you remove it from polling, but ehealth will continue to include it in reports. In the future, you can unretire the element if you want to begin collecting data for it again. The following sections explain why you might want to retire an element rather than delete it. Deleting Elements. A deleted element is one that you no longer want to poll and that you do not want to include in reports. When you delete an element, ehealth removes all data associated with that element from the database. However, ehealth could attempt to rediscover it the next time that you run the discover process for the same IP address. As a best practice, if you do not want to rediscover existing elements that you have deleted, add the IP addresses to an IP exclusion file to filter it out. Follow the instructions provided in the ehealth Resource Discovery Guide. When deleting elements from your poller configuration, keep in mind the following: If you delete a router element, ehealth also deletes all elements associated with that router, such as CPUs, interfaces, and so on. If you delete a system element, ehealth also deletes all elements associated with that system, such as CPUs, disks, partitions, interfaces, process sets, and processes. If the Record detail data option is set in the Modify Element dialog for a system element, you can delete the interface as a subcomponent of the parent as well as an interface element, or retain one of the elements. If you delete a process set, ehealth deletes all of its associated processes as well. If you rediscover the system and choose to find processes, ehealth rediscovers the process set. If you delete an application service element, ehealth also deletes all process sets that are associated with that element.

20 20 Chapter 2 Resolving Polling Errors Before you delete an element, use OneClickEH to right-click it and select Ping from Server. If the element does not respond, confirm that the network has not experienced an outage that could be preventing the element from responding. Ping problems can result from temporary connectivity problems. The element will stop returning ping errors once the network problem is resolved. Once you are certain that the element does not exist and you are sure that you do not want to monitor it, right-click and select Delete; then click OK. Retiring Elements. A retired element is one that you no longer want to poll, but that you want to include in reports until its data ages out or you delete the element. When you retire an element, you retain the old element but do not collect new data for it. You may want to retire an element when you upgrade to a new technology so that you can compare the improvement for the new technology type. The discover process ignores retired elements when it compares newly discovered elements to those in the poller configuration. When you no longer need the element or when data is no longer available for it, you can retire it by right-clicking it and selecting Retire from the OneClickEH menu. Once you have retired an element, ehealth grays out its entry in all OneClickEH element tables. If you want to return a retired element to an active status, right-click the element and select Unretire from the menu. When retiring elements, follow these guidelines and practices: If retired elements still exist in your network and you discover them again, ehealth creates new elements. If you do not want to rediscover them, add their IP addresses to an IP exclusion file for your scheduled Discover jobs. When retiring a parent element, keep in mind that ehealth automatically retires all related child elements that do not consume their own polling licenses. It does not retire child elements for which you have specified Record detail data in the Modify Element dialog. When retiring response source elements, you must first disassociate or remove any Service Availability tests associated with the agent and retire the response source element associated with the agent. Otherwise, you will need to manually edit the svcrsp.cf file to prevent active tests from running on the Service Availability agent. If a different element has been retired with the same agent type and index values, the status bar indicates that an element already exists with these properties. To resolve this problem, change the IP address of one of the retired elements. The information for retired elements must be unique.

21 3 Modifying Your Element Configuration In most cases, interactive and scheduled discovery keeps your element information up-to-date with the latest information from the devices. However, you can manually change the configuration to perform the following tasks: Update element properties. Specify user-defined data to use as an element filter. Make element names more intuitive. Exclude an element from Live Exceptions monitoring. This chapter provides you with guidelines for modifying element information manually and tracking the changes that you and other administrators make to the poller configuration. Updating Element Properties Although discover is able to update elements automatically, you may need to manually update element properties to prevent or resolve discover errors and duplicate elements. Typically, you perform manual updates when the element has changed so drastically that discover cannot match any of its attributes to an existing element, so it considers it a new element. Also, you can perform these changes manually when you need to override the device settings. This might happen when the device configuration is incorrect, but you do not have permission to change the device, or you want to monitor the device in a special way. Any changes that you make to statistics or conversation elements take effect during the next poll. The poller does not need to restart; the changes take effect without interrupting the polling cycle. You can quickly examine the primary properties of an element by selecting Properties from the right-click menu to display the Properties window, as shown in Figure 5. To change a subset of the element s properties, you can double-click the element to display the Edit Element window, as shown in Figure 6. However, to change most element properties, such as agent type, speed, index, you must use the ehealth console. Figure 5. Element Properties Figure 6. Edit Element Window 21