1. Best Practices for Implementing High Availability for SAS® 9.4
Cheryl Doninger, SAS
Zhiyong Li, SAS
Bryan Wolfe, SAS
Copyright © 2010, SAS Institute Inc. All rights reserved.

2. What is HA and Why is it Important for SAS?
Analytics are mission critical to organizations
More and more SAS deployments are operational systems
Large user populations depend on these systems
SAS is mission critical to organizations
Analysts must be able to access the SAS environment at all times
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Copyright © 2013, SAS Institute Inc. All rights reserved.

3. The Goals of this HA Best Practice
Consistent HA strategy for all components
Minimize the number of technologies used for HA
SAS Grid Manager
Clustering
Start with smallest scenario and build to most scalable
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4. SAS Deployment Tiers SAS Metadata Server Tier
SAS Application Server Tier
SAS Web or Middle Tier
SAS Client Tier
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5. Critical Components SAS® Metadata Server (Metadata Server)
SAS Web Server (Web Server)
SAS Web Application Server (Web Application Server)
SAS Web Infrastructure Platform Data Server (WIP Data Server)
SAS JMS Broker (JMS Broker)
SAS Cache Locator (Cache Locator)
SAS Object Spawner (Object Spawner)
SAS OLAP Server (OLAP Server)
SAS Environment Manager Server (EV Server)
SAS Environment Manager Agent (EV Agent)
SAS Deployment Agent (Deployment Agent)
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6. Some Terminology #SASGF13
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7. Bad Things Happen When a Service Goes Down
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8. Active-Passive Mode Cold Standby Node Primary Node #SASGF13
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9. Master-Slave Mode Warm Standby Node Primary Node #SASGF13
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10. Active-Active Mode Cluster #SASGF13
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11. SAS Grid Manager Monitor any/all critical services
Restart on the same node if the service fails
Failover to a standby node if the primary node fails
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12. SAS Grid Manager: Active-Passive
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13. SAS Grid Manager: Active-Active
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14. SAS Metadata Server Cluster
A cluster is three or more metadata server nodes
Each node is a full server with a complete copy of all metadata
One node is designated the master to coordinate the cluster
All other nodes are slave nodes
Clients connect to slave nodes
Once connected the cluster behaves like a normal server
A metadata server cluster is a group of three or more nodes configured as identical metadata servers. Each node typically runs on an independent physical or virtual machine and has its own server configuration directory, configuration files, journal file, and logs. The nodes work together so that they each have synchronized on disk and in memory copies of the metadata.
Common question is whether I can decide which is the master – thinking I can put point it to the biggest machine for performance gains. It’s important to note that the master’s main job is to coordinate updates (as we’ll see on subsequent slides). Read requests are handled by the slaves. So trying to engineer performance gains isn’t something you would want to try to do. And as nodes go down & come up, different ones may serve as the master at different times.
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Copyright © 2013, SAS Institute Inc. All rights reserved.

15. Three Node SAS Metadata Server Cluster
MASTER
SHARED BACKUP
NODE2
SLAVE
SLAVE
NODE1
NODE3
A metadata server cluster is a group of three or more nodes configured as identical metadata servers. Each node typically runs on an independent physical or virtual machine and has its own server configuration directory, configuration files, journal file, and logs. The nodes work together so that they each have synchronized on disk and in memory copies of the metadata.
Common question is whether I can decide which is the master – thinking I can put point it to the biggest machine for performance gains. It’s important to note that the master’s main job is to coordinate updates (as we’ll see on subsequent slides). Read requests are handled by the slaves. So trying to engineer performance gains isn’t something you would want to try to do. And as nodes go down & come up, different ones may serve as the master at different times.
#SASGF13
Copyright © 2013, SAS Institute Inc. All rights reserved.

16. SAS Web Application Server Cluster
SAS Web Server (Load-balance / reverse-proxy)
SAS Web Application Server
SAS Web Application Server
SAS Web Application Server
Web Applications*
Web Services
Web Applications*
Web Services
Web Applications*
Web Services
SAS Web Infrastructure Platform Data Server
SAS Web Infrastructure Platform Data Server
SAS Web Infrastructure Platform Data Server
Cache Locator
Cache Locator
Cache Locator
JMS Broker
JMS Broker
JMS Broker
* Not all SAS Web Applications support clustering due to technical limitations.
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Copyright © 2013, SAS Institute Inc. All rights reserved.

17. Legend “SGM restart/cold failover” “Warm failover”
SAS Grid Manager monitors active service instance and restarts on same machine or starts a new instance on a cold standby machine if the original machine dies
Requires a failover machine
Can apply to both active/passive and active/active
Parentheses ( ) denote cold standby for failover
“Warm failover”
Master-slave mode
Chevrons < > denote warm standby, the slave node of master/slave cluster
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18. Legend (continued) “Clustered and SGM Restart” “SGM restart”
Clustering capability native to the service will be used
SAS Grid Manager monitors active service instance and restarts on same machine
There is no standby machine if the original machine dies
Services on multiple machines without ( ) indicate clustering
“SGM restart”
SAS Grid manager monitors a service instance and restarts the service on the same machine
These services have 1-1 mapping per node
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20. Talking Points... Component Shared Config Per-node Config Mode
Metadata Server X
active-passive
Object Spawner
OLAP Server
Web Server
EV Agent
n/a
WIP Data Server
master-slave
EV Server
JMS Broker
Web Application Server
active-active
Cache Locator
#SASGF13
Copyright © 2013, SAS Institute Inc. All rights reserved.

22. Talking Points... Component Shared Config Per-node Config Mode
Metadata Server X
active-active
Object Spawner
active-passive
OLAP Server
Web Server
EV Agent
n/a
WIP Data Server
master-slave
EV Server
JMS Broker
Web Application Server
Cache Locator
#SASGF13
Copyright © 2013, SAS Institute Inc. All rights reserved.

24. Talking Points... Component Shared Config Per-node Config Mode
* active-active w/ proper licensing
Component
Shared Config
Per-node Config
Mode
Metadata Server X
active-active
Object Spawner
active-passive *
OLAP Server
Web Server
active-passive
EV Agent
n/a
WIP Data Server
master-slave
EV Server
JMS Broker
Web Application Server
Cache Locator
#SASGF13
Copyright © 2013, SAS Institute Inc. All rights reserved.

26. Talking Points... Component Shared Config Per-node Config Mode
* active-active w/ proper licensing
Component
Shared Config
Per-node Config
Mode
Metadata Server X
active-active
Object Spawner
active-passive *
OLAP Server
Web Server
active-passive
EV Agent
n/a
WIP Data Server
master-slave
EV Server
JMS Broker
Web Application Server
Cache Locator
#SASGF13
Copyright © 2013, SAS Institute Inc. All rights reserved.

27. Summary
SAS is mission critical and, therefore, must be highly available
SAS Grid Manager + Clustering
HA across entire software stack with most functionality
SAS Grid Manager – Clustering
No load balancing capabilities
Clustering – SAS Grid Manager
No automatic restart and failover capabilities
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Copyright © 2013, SAS Institute Inc. All rights reserved.

28. More Information...
SAS 9.4 Intelligence Platform: Middle-Tier Administration Guide, Second Edition.
“Using Metadata Server Clustering.” In SAS 9.4 Intelligence Platform: System Administration Guide
“Understanding Server Load Balancing.” In SAS 9.4 Intelligence Platform: Application Server Administration Guide.
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29. ??? Questions ???
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