Extreme Networks Px Series manual Server Startup Pacing

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Server Startup Pacing

In order not to overload a server that has just come up, server startup pacing restricts the number of connections that the server can process. Startup pacing is performed when health checks bring a server back online, or when a server is enabled, if health checking is disabled for that server's server group. Server startup pacing is enabled by default. To enable and disable it, use the following commands:

enable server-startup-pacing

disable server-startup-pacing

The number of connections over time for a particular server are calculated from an initial maximum number of connections, and an interval.

•To set the global initial maximum, use the following command:

config server-startup-pacing initial-limit <number of connections>

The initial maximum defaults to 5 connections.

•To set the global interval, use the following command: config server-startup-pacing interval <seconds>

The interval defaults to 5 seconds.

When a server is brought up, connections are limited to the initial maximum number. After the number of seconds configured for the interval, the maximum number of connections allowed is doubled. It is doubled after each interval, until it reaches the configured maximum for that server, as specified by the max-connectionsargument to config server. See “Configuring Real Servers” on page 5-1.

For example, using the default values, the connections are limited to 5 when the server first comes up. After the first five seconds, the number of allowed connections is 10, after the next 5 seconds, 20, then 40, and so on, until the number reaches the server’s maximum-connectionsvalue.

9-2	Px Series Application Switch Installation and Configuration Guide

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Contents Published April Part number 100101-00 Rev Page Contents Installing the PxM Application Switch Module Configuring Servers and Services Index Index of Commands Preface IntroductionConventions Text ConventionsIcon Alerts you to Convention DescriptionRelated Publications Preface Server Load Balancing Concepts Purpose of Server Load BalancingTerms 1Conceptual view of server load balancingLoad Balancing Modes Layer 4 Load BalancingLayer 7 Load Balancing and Content Analysis 2Single client-server transaction using layer3Establishing a layer 7 request Getting Started on Load Balancing Configuration Port RewriteGetting Started on Load Balancing Configuration Page Overview of the SummitPx1 Application Switch Installing the SummitPx1 Application SwitchSummitPx1 Front View 1Px series application switch LEDs Color IndicatesSummitPx1 Application Switch Rear View Signal Description2DB-9 Adapter Pinouts To DB-9Determining the Location Installing the SummitPx1 Application SwitchRack Mounting Powering On the SummitPx1 Free-StandingSetting Up Console Communication Configuring Switch IP Parameters Configuring the 10/100 Ethernet Management Port Installing the PxM Application Switch Module Installing I/O ModulesRemoving I/O Modules Removing I/O Modules Page Managing the Switch Using the Command-Line Interface Abbreviated Syntax and Command CompletionSyntax Symbols 1Command Syntax SymbolsSymbol Description Line-Editing KeysSpecifying Text Values 2Line-Editing KeysCommand History Configuring Management AccessPrompt Text Changing the Default Passwords Creating Accounts Modifying AccountsCommand Description Managing the PxMConfiguring VLANs Configuring Snmp 4SNMP Configuration SettingsSetting Description System ContactConfiguring DNS Client Services SettingDescriptionUsing Secure Shell 2 SSH2 5DNS Client Configuration CommandsEnabling SSH2 for Inbound Switch Access Config ssh2 keyUsing SCP2 from an External SSH2 Client SSH2 Client Functions on the Switch Showing CPU Load UtilitiesChecking Basic Connectivity Logging Configuring a Startup Banner Message Starting the GlobalPx Content Director AgentExample Configuration Internet DNS serverFollowing commands configure all system-related facilities Page Configuring Servers and Services Configuring Real ServersConfiguring Server Groups Configuring Virtual Services Layer 7 Virtual Services Layer 4 Port-based Load BalancingConfiguring Traffic Tagging 1Tag Specifications Configuration ExampleTag Specification Description Tag Range Configuration Example Page Choosing Policies, Persistence Modes, and NAT Scheduling Policies1Scheduling Policies Persistence ModesSpecifier Policy Description Client IP Persistence Mode UDP Flow Persistence1Client IP persistence mode Configuring Client IP Stickiness Cookie Persistence Modes2Self-identifying cookie persistence mode Persistence Modes Hashed Cookie Persistence Session Learned Cookie Persistence Mode 4Learned cookie persistence mode Configuring Cookie Stickiness SSL Session Identifier Persistence Full-NAT Mode NAT ModesServer-only Half-NAT Mode Configuring Full-NAT Mode and Proxy IP AddressesConfiguring Half-NAT Mode Config source-flow name next-hop gateway-mode ip Real Syslog server SummitPx1 Configuration Example Page URL Switching Domain and URL SwitchingDomain Switching 1Typical switching scenario2Domain switching example Configuring URL Switching URL Switching3Simple URL switching example 4More Complicated URL switching example 5Hierarchical approach to pattern rules 1Wildcard Combinations Creating Domain and URL Switching RulesWildcard Example Definition Modifying Existing URL Rules and Domains Application Servers Management net Configuration Example Page Configuring Redundancy Using Vrrp with the SummitPx1Adding and Configuring VRRPs Give backup systems lower prioritiesUsing Vrrp in Existing Redundant Networks 1Application switch using multiple VLANs Vrrp Automatic SynchronizationFollowing commands can be passed from master to backup Configuring Redundancy for the PxM Using Esrp with the PxMConfiguring the PxM for Multiple VLANs For SW2Configuring a Default Gateway Health Checks OverviewServer Startup Pacing Health Checking Procedure Timers and Counters Configuring Health ChecksTypes of Health Checks You can disable health checks for a server group Page 1Statistics Display Commands Monitoring the SwitchShowing Traffic Statistics Displays packet-level counters for Showing Configuration Details 2Configuration Display CommandsConfiguration Displays Status Displays SummitPx128 # show server detailsShow health Information Column DescriptionManaging and Troubleshooting Operation 5Management and Troubleshooting CommandsCommandDescription Index EsrpHttp GET AUX Page Index of Commands