Oracle Real Application cluster evolves with each release. There are some important features added in Oracle 11GR2. During this presentation the authors will share their practical experience on how to configure EBS to use SCAN Listeners, services and load balance different EBS components across cluster nodes. We will talk through different configuration strategies and how to choose the right one. Come to the presentation and take away practical hints on how to make EBS and RAC 11GR2 best friends.
7. SCAN Introduction
• Single Client Access Name
• Addresses the TNSNAMES multi address issue
• Old - 10G FAILOVER
• Complex TNS entries
• Complex to manage (add a node)
• Previous Oracle Clients support
• New - 11GR2
• One Simple TNS entry on client side
• Easy to add nodes (address forwarding)
• Transparent to Oracle Client versions
• Load balancing & Failover management on Cluster side
8. SCAN Introduction
scan.clustgrid-prod.yourdomain.com + service
RAC: Frequently Asked Questions [ID 220970.1]
How to Troubleshoot Connectivity Issue with 11gR2 SCAN Name [ID 975457.1]
11gR2 Grid Infrastructure SCAN Explained [ID 887522.1]
SCAN & EBS 11i [ID 823581.1 ] R12 [823587.1]
Oracle 11G SCAN: Concepts and Implementation Experience Sharing
9. DNS resolves
scan-cluster_a.mycomany.com
to 3 SCAN IP addresses
SCAN (remote) listeners register
and distribute information about
local listeners serving a SERVICE
LISTENER LISTENER LISTENER
2.
Oracle Instance:
1. registers SERVICES it running in
LOCAL listeners
LISTENER
2. registers LOCAL listeners serving remote_listener (default)
a service in SCAN listeners
1. LISTENER_ERP
(custom)
local_listener Node 2
service_name
Node 1
10. SCAN & Apps
• R12 Apps & SCAN integration is optional
• Apps could be configured to use traditional failover setup
• Third party applications can leverage SCAN if necessary
• R12 & SCAN
• There is a separate Apps listener
• Running from Apps DB home
• Managed by crvstl utility
12. SCAN & Apps Implementation
Using Oracle 11g Release 2 Real Application Clusters with
Oracle E-Business Suite Release 12 [ID 823587.1]
Appendix D : Enabling/Disabling SCAN Listener Support in Autoconfig
• Step1: Configure SCAN context variables on DB nodes
<scanName oa_var="s_scan_name">
mg-prod-oda01
<scanPort oa_var="s_scan_port">
1524
<scanUpdateFlag oa_var="s_update_scan">
TRUE
13. SCAN & Apps Implementation
• s_scan_name
• a SCAN name used during initial RAC installation. This name should be
resolved all SCAN IP addresses by a network DNS service and
shouldn’t be defined in any hosts file
• s_scan_port
• a port SCAN listeners are listening on. This port is defined during initial
RAC installation
• s_update_scan
• instructs AutoConfig to update database with the parameters specified
earlier (s_scan_name and s_scan_port)
14. SCAN & Apps Implementation
• s_db_listener
• EBS listener name. EBS uses local listener started from EBS database oracle
home. Note that the name should be in the LISTENER_<ENV> formant on all DB
nodes. This allows to define and manage the listeners as one listener cluster
resource across all RAC nodes
• s_dbport
• EBS listener port. This port should be different from Cluster’s VIP listener port
• Both EBS local and Cluster’s local listeners uses the same VIP addresses
• s_instRemoteListener
• the variable sets remote_listener parameter in the init.ora file. The variable is set
by AutoConfig utility if s_update_scan variable is set to TRUE.
• s_instLocalListener
• the variable sets local_listener parameter in the init.ora file. The variable it
updated by AutoConfig utility if s_update_scan variable is set to TRUE.
15. SCAN & Apps Implementation
• Step 2: Run AutoConfig on ALL database nodes
• updates database init.ora
• generates SCAN related configuration files
• populates several tables including
• FND_DATABASES => IS_RAC_DB, SCAN_NAME,SCAN_PORT
• FND_TNS_ALIASES
• FND_DATABASE_INSTANCES …
• It is very important AutoConfig executed successfully on
ALL RAC nodes
16. SCAN & Apps Implementation
• Step 3: Run AutoConfig on ALL application nodes
• generate INST1, INST2, etc and <SID>_BALANCE tns
aliases that uses the SCAN parameters
• Verify that ALL tns aliases reference SCAN listener
• INSTANCE_NAME=INSTx
• All set
• Check SCAN & EBS listeners
• Check connectivity from apps nodes
21. Default configuration
• Good for small & other provisioned hardware systems
• Pros
• easy to configure and maintain
• high availability out of the box
• allows smaller number of apps nodes
• Cons
• opened to performance issues
23. Parallel Concurrent Processing
• Pros
• controlled load partitioning
• controlled high availability
• good performance
• Cons
• requires at least the same number of apps nodes as DB
nodes
• expensive to maintain
25. Target Instance
• Pros
• functional load partitioning
• good performance
• doesn’t requires the same number of applications nodes as
RAC nodes
• Cons
• complex to maintain
• limited fail-over options
• can use instances names only (tns aliases)
• doesn’t support all concurrent programs / managers
27. Using Services (vision)
• Pros
• No dependences from number of Apps nodes
• Easy and well planed failover
• Leverages setup we are use for years now
• Single service balances across one or many nodes
• Easy switchover or reconfiguration
• Most reconfiguration is online
• Leverages Oracle 11GR2 Cluster services
• Resource manager
• Resources (e.g. CPU, IO, etc) per service (e.g. payroll,
finance, etc.)
• Cons
• Oracle Dev work :)
29. Conclusions
• SCAN is One of the biggest Cluster 11GR2 features
• Oracle Applications R12 supports SCAN
• Implementation is optional
• There are still missing bits (services support)
• You should be careful implementing SCAN
• There are some know issues
• You should consider functional load partitioning for big
and active systems
• Today the options are still a bit limited