Load Balancing and Failover with Oracle 10gR2 RAC

Transcription

1 <Insert Picture Here> Load Balancing and Failover with Oracle 10gR2 RAC Barb Lundhild Oracle Corporation RAC Product Management The following is intended to outline our general product direction. It is intended for information purposes only, and may not be incorporated into any contract. It is not a commitment to deliver any material, code, or functionality, and should not be relied upon in making purchasing decisions. The development, release, and timing of any features or functionality described for Oracle s products remains at the sole discretion of Oracle. Page 1 1

2 Confused? Server-side load balancing Client load balancing Runtime connection load balancing Connection load balancing Session load balancing Listener load balancing Introduction Key Items to Load Balancing with Oracle Oracle Net Services Connection Load Balancing Automatic Workload Management Connection Pools Parallel Execution Page 2 2

3 Single Instance What do you do when there is more than one? Real Application Clusters Page 3 3

4 Oracle Net Services Connection Load Balancing Two types of load balancing Client Side Load Balancing Server Side Load Balancing Best Practice is to set up both in a Real Application Clusters environment Client-Side Connection Load Balancing sales.us.acme.com= (DESCRIPTION= (ADDRESS_LIST= (LOAD_BALANCE=on) (ADDRESS= (PROTOCOL=tcp) (HOST=sales1-vip) (PORT=1521)) (ADDRESS= (PROTOCOL=tcp) (HOST=sales2-vip) Clients Listeners (PORT=1521))) (CONNECT_DATA= (SERVICE_NAME= sales.us.acme.com))) Page 4 4

5 Server Side Connection Load Balancing Listener will load balance incoming connections across all nodes actively providing a service Directs connection to the least loaded node Use parameters LOCAL_LISTENER, REMOTE_LISTENER to ensure instances register services with all listeners Server Side Connection Load Balancing LISTENER Service OLTP? PMDB1 on N1 Application Server Network PMDB2 on N2 PMDB3 on N3 Network RAC Database Page 5 5

6 Connection Load Balancing LISTENER Service OLTP? PMDB1 on N1 Network Listeners Clients RAC Database What if there are Multiple Applications? Page 6 6

7 Automatic Workload Management Application workloads can be defined as Services Individually managed and controlled Assigned to instances during normal startup On instance failure, automatic re-assignment Service performance individually tracked Finer grained control with Resource Manager Integrated with other Oracle tools / facilities (E.G. Scheduler, Streams) Use EM to Define Services Page 7 7

8 Automatic Workload Management Order Entry Spare Supply Chain Normal Server Allocation Page 8 8

9 Automatic Workload Management Order Entry Spare Supply Chain Server Failure Automatic Workload Management Order Entry Supply Chain Re-allocate spare to Order Entry Page 9 9

10 Automatic Workload Management Order Entry Supply Chain Application Resource Requirements Grow Many Services, one DB Node-1 Node-2 OLTP 1 Node-3 Node-4 Node-5 Node-6 OLTP 2 OLTP 3 Repor ting Batch DW OLTP 4 Page 10 10

11 Distributed Transaction Processing with RAC All branches of a tightly coupled distributed transaction must run on same instance Better handling of distributed transactions (XA, MS DTC) through DTP services dbms_service.modify_service (service_name=> my.dtp.enabled.service, DTP=>TRUE) Service has 1 preferred instance and guarantee only one active instance Create more services than RAC instances, assign groups of transactions to each service Improved XA Support with RAC Tightly coupled Global txns can span RAC instances CLUSTERWIDE_DISTRIBUTED_TRANSACTIONS, which is TRUE by default Allows the units of work performed across these Oracle RAC instances to share resources and act as a single transaction I.E. tightly coupled 2PC requests can be sent to any node in the cluster Page 11 11

12 Services Best Practices Always connect with a service If you do a srvctl stop database, you must do a srvctl start service after the srvctl start database Use server-side callout to enforce startup XA Applications should use DTP services Service configuration can be changed dynamically Connection Pools c c c c c c c c c c c c Application Connection Pool Real Application Clusters Page 12 12

13 Load Balancing Advisory Load Balancing Advisory is an advisory for balancing work across RAC instances. Load balancing advice Is available to ALL applications that send work. Directs work to where services are executing well and resources are available. Adjusts distribution for different power nodes, different priority and shape workloads, changing demand. Stops sending work to slow, hung, failed nodes early. Load Balancing Advisory in Nut Shell Uses DBMS_SERVICE.GOAL Service time weighted moving average of elapsed time Throughput weighted moving average of throughput AWR Calculates goodness locally, forwards to master mmon Master mmon builds advisory for distribution of work Records advice to SYS$SERVICE_METRICS Posts load balancing advice via FAN event to AQ, PMON, ONS Load Balancing Advisory Users Use percentages and flags to send work, gravitate work. Page 13 13

14 GV$SERVICEMETRIC Service Time Service Instance msec/call CPU_TIME DB_TIME THROUGHPUT SRV1 SSKY SRV1 SSKY SSKYDB SSKY SSKYDB SSKY SYS$BACKGROUND SSKY set pages 60 space 2 lines 132 num 8 verify off feedback off column user_data heading "AQ Service Metrics" format A60 wrap break on SERVICE_NAME skip 1 select to_char(enq_time, 'HH:MI:SS') Enq_time, user_data from SYS.SYS$SERVICE_METRICS_TAB order by 1; Load Balancing Advisory Page 14 14

15 Fast Application Notification (FAN) RAC notification mechanism which let applications know about service & node events (UP or DOWN events) and Load Balancing Advisory events Events published using Oracle Notification Service (JDBC) and Advanced Queues (OCI, ODP.NET) Runtime Connection Load Balancing Solves the Connection Pool problem! Easiest way to take advantage of Load Balancing Advisory No application changes required No extra charge software to buy Enabled by parameter on datasource definition Supported by JDBC and ODP.NET Page 15 15

16 Runtime Connection Load Balancing Client connection pool is integrated with RAC load balancing advisory When application does getconnection, the connection given is the one that will provide the best service. Policy defined by setting GOAL on Service Need to have Connection Load Balancing Load Balancing Advisory Goals THROUGHPUT Work requests are directed based on throughput. SERVICE_TIME Work requests are directed based on response time. None Default setting, turn off advisory execute dbms_service.modify_service (service_name => 'test' -, aq_ha_notifications => true -, clb_goal => dbms_service.clb_goal_short -,goal=>dbms_service.goal_service_time); Page 16 16

17 Step 1. Enable Cache and Fast Connection Failover, Remote ONS Set data source properties OracleDataSource ods = new OracleDataSource()... ods.setuser(scott); ods.setpassword(tiger); ods.setconnectioncachingenabled(true); ods.setfastconnectionfailoverenabled(true); Ods.setONSConfiguration("nodes=host1:6200,host2:6200"); ods.setconnectioncachename(mycache); ods.setconnectioncacheproperties(cp); ods.seturl("jdbc:oracle:thin:@(description= (LOAD_BALANCE=on) (ADDRESS=(PROTOCOL=TCP)(HOST=VIP1)(PORT=1521)) (ADDRESS=(PROTOCOL=TCP)(HOST=VIP2)(PORT=1521)) (CONNECT_DATA=(SERVICE_NAME=MYSERVICE)))"); or set system properties -D oracle.jdbc.fastconnectionfailover=true Step 2. Verify ONS on RAC nodes $ORACLE_HOME/opmn/conf/ons.config localport=6100 # port ONS is writing to remoteport=6200 # port ONS is listening on loglevel=3 useocr=on Page 17 17

18 Step 3. When starting the application.. Specify system property -Doracle.ons.oraclehome=<ORACLE_HOME-onclient> Ensure ons.jar file is on the CLASSPATH. SEE RAC SAMPLE CODE for FAST START GUIDE Runtime Connection Load Balancing with OCI Session Pools The application must have been linked with the threads library. The OCI environment must be created in OCI_EVENTS and OCI_THREADED mode. Configure the RAC service with a GOAL, CLB_GOAL, and AQ_NOTIFICATIONS to TRUE. dbms_service.modify_service(service_name=> crm, aq_ha_notifications=>true, goal=>service_time, clb_goal=>short); Page 18 18

19 Runtime Connection Load Balancing with JDBC, ODP.NET CRM requests connection connection cache? 60% 10% 30% CRM is bored CRM is very busy CRM is busy Instance 1 Instance 2 Instance 3 Heavy batch starts one node - Average user calls/second No Load Balancing Service Time Goal Throughput Goal Page 19 19

20 Goal = NONE (off) Service 01 - elapsed time per call elapercall (ms) Node 1 Node :09:22 21:14:02 21:18:43 21:23:35 21:28:22 21:33:04 21:37:45 time Goal = SERVICE_TIME Service S01 - elapsed time per call elapsed node 1 elapsed node elapercall (ms) :43:24 18:48:05 18:52:48 18:57:31 19:02:18 19:07:03 19:11:48 time Page 20 20

21 Fast Connection Failover Supports multiple connection caches Datasource for each cache mapped to a service Keeps track of service and instance for each connection Cleans up connections when failures occur Distributes new work requests across available instances Mid-Tier Database Tier CACHES SERVICE 1 INST X SERVICE 2 INST Y SERVICE 3 INST Z JDBC, ODP.NET, OCI Failure Notification (FaN) JDBC Fast Connection Failover Processing When DOWN signal received from Oracle Database 10g RAC Routes new requests to surviving instances Throws exception if application was in midst of transaction When UP signal received from Oracle Database 10g RAC Creates new connections to new instances Distributes new work requests evenly to all available instances Page 21 21

22 Extended FAN/FCF Client Integration Oracle Call Interface standalone,taf, connection pool, and session pool connections are automatically broken and cleaned up by OCI and the application callback is invoked within seconds of the failure event. ODP.NET FAN notifies ODP.NET which allows it to clean up resources from severed connections or establish new connections HA Events=true; on connection string Service must have aq_ha_notifications=>true Summary For best workload balancing with Real Application Clusters: Use Connection Load Balancing Use Automatic Workload Management (Services) When using Connection Pools, use Fast Connection Failover and Runtime Connection Load Balancing Page 22 22

23 For More Information TWP : Workload Management with Oracle Database 10g Sample Code for RAC Oracle Clusterware and RAC Admin and Deployment Guide (Chapt 6) Q & A Q U E S T I O N S A N S W E R S Page 23 23

24 For More Information REAL APPLICATION CLUSTERS or otn.oracle.com/rac Page 24 24

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