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Click to edit Master title style,Click to edit Master text styles,Second level,Third level,#,Load Balancing,Static Methods,Round Robin(RR),Ratio(Weighted Round Robin),Distributes connections in a RR fashion for members/nodes whose ratio has not been met,Dynamic Methods*,Least Connections,Fewest connections at the moment the load balancing decision is being made,Fastest,v9.0-v9.3.1 not implemented,defaults to round robin(issued tracked in CR22586),v9.4 and higher base on outstanding Layer 7 requests and open L4 connections,Both a TCP and Layer 7 profiles are required,If there is no Layer 7 profile on the virtual server,defaults to least connections,Observed,Calculates a ratio each second for each member based on the number of layer 4 connections and then load balances based on that ratio,Predictive,Differs from Observed mode in that it looks at the change between the previous connection counts and the current connection counts,Dynamic Ratio,Dynamically weights servers based on results SNMP/WMI queries,Requires SNMP_DCA,SNMP_Base or WMI monitoring of pool,Load Balancing Methods,*SOL6406-Change in Behavior:Fastest,Observed,and Predictive load balancing modes,Load Balancing,Load balancing a service(,member,)versus IP address(,node,),Member,-look only at the statistics of the targeted pool,Node,-look at all pools a containing the IP addresses(nodes)of the targeted pool,http_vs,1.1.1.1:80,secure_vs,1.1.1.1:443,Request,Which,pool,member,has the fewest connections,Which,node,has the fewest connections,Least Connections(member),Least Connections(Node),Server_A,3.3.3.100,Server_B,3.3.3.101,605 conns,http_pool,5 conns,10 conns,secure_pool,600 conns,200 conns,210 conns,web_pool,Priority=5,Activation 2,Load Balancing,Two Basic Pool Failure Mechanisms,Fallback Host,(for HTTP and HTTPS applications),Is the server of last resort if all pool members are unavailable,HTTP redirect(http 302)is returned to client,Configured in the HTTP profile,the fallback host is not monitored,Priority Group Activation,Ability to dynamically pull in new members into the pool,Lower priority groups are pull into higher priority groups,All members of a priority group are pull in a together,ftp_pool,Priority=5,Activation 3,Backup Servers,Running WWW and FTP,Priority=1,Default,Gateway,Pool,Default Gateway Pools,Load balancing doesnt have to just be inbound,def_gw,_vs,0.0.0.0/0,auto,lasthop,VLAN isp69,Network 69.9.9.0/24,SNATpool,69.9.9.20-29,VLAN isp205,Network 205.5.5.0/24,SNATpool,205.5.5.20-29,Which gateway is,best?,request,DST:,SRC:10.10.1.29,request,DST:,SRC:205.5.5.29,69.9.9.1,205.5.5.1,Internet,IP 10.10.1.29 GW 10.10.1.1,VLAN Internal,SelfIP 10.10.1.1,Load Balancing,LAB 3 Load Balancing,Ratio Lab,Priority Group Lab,Monitors,Monitors,A monitor is a test of a specific application,for an expected response,within a given time.,The administrator can configure the interval between checks and when the monitor times out.,Interval,is the time between each check,Timeout,is the length of time for a successful check to be received before the node is marked down,The LTM can use composite monitors,so multiple checks can be applied!,All or some of the monitors can be used to determine member status,Monitors can also use reverse logic,Monitors(cont.),Node Checks,Determine availability of all services for a particular node,Example:ICMP check,is the node pingable,When check fails,node is pull from all pools it has membership in,Service Checks,Checks connectivity to services/ports,Example:HTTP check,can port 80 be opened,Content Checks,Queries the service and checks the contents of the query,Example:HTTP GET/,is the page returning with correct content,Content checks can involve username and passwords,Path Checks,Are transparent monitors checking through devices to verify a path exists,Or used to monitor applications outside the pool,that are required for the pool to function,Interactive Checks,Custom scripts can be created to interact with application,Examples are in/usr/bin/monitors and,Monitor Types in GUI(partial list),Simple monitors,ICMP,checks the status of a node,using Internet Control Message Protocol(ICMP).,Gateway ICMP,checks nodes in a pool that implements gateway failsafe for high availability.,TCP Echo,checks the status of a node,using Transmission Control Protocol(TCP).,Extended Content Verification(ECV)monitors,TCP,verifies the Transmission Control Protocol(TCP)service by attempting to receive specific content from a node.,HTTP,verifies the Hypertext Transfer Protocol(HTTP)service by attempting to receive specific content from a web page.,HTTPS,verifies the Hypertext Transfer Protocol Secure(HTTPS)service by attempting to receive specific content from a web page protected by Secure Socket Layer(SSL)security.,Extended Application Verification(EAV)monitors,External,allows users to monitor services using their own programs.,FTP,verifies the File Transfer Protocol(FTP)service by attempting to download a specific file to the,/var/tmp,directory on an LTM system.Once downloaded successfully,the file is notsaved.,IMAP,Verifies the Internet Message Access Protocol(IMAP)by attempting to open a specified mail folder on a server.This monitor is similar to the,pop3,monitor.,LDAP,Verifies the Lightweight Directory Access Protocol(LDAP)service by attempting to authenticate the specified user.,MSSQL,Verifies Microsoft Windows SQL-based services.,NNTP,Verifies the Usenet News protocol(NNTP)service by attempting to retrieve a newsgroup identification string from the server.,Monitor Types,EAV monitors(continued),Oracle,Verifies services based on Oracle by attempting to perform an Oracle login to a service.,POP3,Verifies the Post Office Protocol(pop3)service by attempting to connect to a pool,pool member,or node,log on as the specified user,and log off.,RADIUS,verifies the Remote Access Dial-in User Service(RADIUS)service by attempting to authenticate the specified user.,Real Server,checks the performance of a pool,pool member,or node that is running the RealServer data collection agent,and then dynamically load balances traffic accordingly.,SIP,checks the status of Session Initiation Protocol(SIP)Call-ID services on a device.The SIP protocol enables real-time messaging,voice,data,and video.,SMTP,checks the status of a pool,pool member,or node by issuing standard Simple Mail Transport Protocol(SMTP)commands.,SNMP DCA,Checks the current CPU,memory,and disk usage of a pool,pool member,or node that is running an SNMP data collection agent,and then dynamically load balances traffic accordingly.,SNMP DCA Base,Checks the current user usage of a pool,pool member,or node that is running an SNMP data collection agent,and then dynamically load balances traffic accordingly.The way that you configure the monitor settings determines the data that the LTM system collects.,SOAP,Tests a Web service based on the Simple Object Access Protocol(SOAP).,UDP,Verifies the User Datagram Protocol(UDP)service by attempting to send UDP packets to a pool,pool member,or node and receiving a reply.,WMI,Checks the performance of a pool,pool member,or node that is running the Windows Management Infrastructure(WMI)data collection agent and then dynamically load balances traffic accordingly.,Monitor Status Reporting,Statuses are base on monitor response and object hierarchy.,The Virtual Server status is affected by the status of the Pool,The Pool status is affected by the status of Pool Members,A Pool Member is affected by the status of the node that supports it,What happens when a monitor fails,When a monitor check fails,the member becomes suspect,LTM sends no NEW connections to the member,existing connections are maintained,If there is a successful check before the timeout value is reached,things continue normally,If the monitor failures exceed the timeout value,the member is removed from the pool,connections are reaped,Monitor Status Reporting,Status(Color),Status Definition,Available(Green),General:,Child monitor successful,Parent at least one Child is Green,Node:,Most recent monitor successful,Pool Member:,Most recent monitor successful,Pool:,At least one,Pool Member is available,Virtual Server:,At least one,Pool is available,Unknown(Blue),General:,Child no associated monitor(or timeout of first check not reached),Parent all child objects are unknown(blue),Node:,No associated monitor(or timeout of first check not reached and not successful),Pool Member:,No associated monitor(or timeout of first check not reached and not successful),Pool:,All Pool Members are unknown(blue),Virtual Server:,All Pools are unknown(blue),Offline(Red),General:,Child monitor failed,Parent at least one Child red AND no green or yellow children available,Node:,Most recent monitor failed(no successful checks within timeout period),Pool Member:,Most recent monitor failed(no successful checks within timeout period),Pool:,One or more members are offline and no members are available,Virtual Server:,One or more pools offline and no members available,Up Interval(v10.1+),Allows for an effective combination of active and inband monitors,Found Under the Configuration:,Advanced,menu for each monitor,there are two components.,Up Interval,Disabled(default),:Monitor uses,Interval,for checks,Enabled,:You can specify a different interval to use when the resource checked is,up,.,Time Until Up,The number of seconds to wait after a resource first responds correctly before setting the resource to,up,.,During this interval,all,checks must be successful.,When the interval expires,the resource is marked,up,.,The default is,0,meaning that the resource is marked,up,immediately upon receipt of the first correct response.,Another notable setting is,Manual Resume,When marked,Yes,the pool member is,Disabled,requiring operator intervention.,
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