| Question |
| What are the cluster components need to be considered as cluster practices? |
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| Answer |
| Networks :- HACMP is a network centric application. Adapters :- Each network defined to HACMP should have at least two adapters per node. Applications :- The most important part of making an application run well in an HACMP cluster is understanding the application’s requirements Application Data Location :- Where should application binaries and configuration data reside? Start/Stop Scripts :- Application start scripts should not assume the status of the environment. Application Monitoring HACMP provides the ability to monitor the state of an application. Application Provisioning :- |
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| Question |
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| What the pre-requisite to configure HACMP ? |
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| Basic pre-requisites as below. Shared external disk devices :- Each node has access to one or more shared external disk devices. A shared external disk device is a disk physically connected to multiple nodes. Networks As an independent, layered component of AIX, the HACMP software is designed to work with any TCP/IP-based network. Min. 2 Ethernet Adapter Clients A client is a processor that can access the nodes in a cluster over a local area network. |
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| Question |
| Why is netmon.cf required and what are its contents? |
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| Provides network monitoring functions Path for this file is /usr/sbin/rsct/samples/hats/netmon.cf The netmon.cf file is an optional configuration file that customers can put in place to augment the normally available ping targets with any hosts on the network that are not defined to be part of the cluster itself, and thus would not be picked up automatically, but are reachable from the cluster nodes, specifically from the IP addresses being monitored by topology services. Location /usr/es/sbin/cluster/netmon.cf Location of the netmon.cf file in a PowerHA environment /var/ct/cfg/netmon.cf Location of the netmon.cf file in an RSCT peer domain |
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| Question |
| How many types are IP’s need to configure in HACMP and what is there purpose ? |
| Answer |
| – Boot IP is the original address on a network interface even when the cluster is down – Service IP is a movable IP that will be added to a network interface when a resource group becomes online. Clients normally should connect to service IP. If a resource group fails over to another node, service IP will be moved there – Persistent IP comes to life when cluster is up, but it does not move to other nodes. As the name implies, it persists to remain on the node it should be. Persistent IPs are usually defined for maintenance purpose by HACMP admin. |
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| Question |
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| What is application monitors and how do we configure it? |
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| Answer |
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| You can configure multiple application monitors and associate them with one or more application servers. By supporting multiple monitors per application, HACMP can support more complex configurations. For example, you can configure one monitor for each instance of an Oracle parallel server in use. Or, you can configure a custom monitor to check the health of the database, and a process termination monitor to instantly detect termination of the database process. You can also specify a mode for an application monitor. It can either track how the application is being run (running mode), or whether the application has started successfully (application startup mode). Using a monitor to watch the application startup is especially useful for complex cluster configurations. |
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| Question |
| Tell us importance of Application servers n HACMP. Also, should Application server be deployed for Databases as well as Applications like CBS, netbanking etc. |
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| Yes, We can deploy databases as well application mentioned by you. To do this we need to create the resource group which will have the application server should also contain all the resources that the application depends on, including service IP addresses, volume groups, and file systems. Once such a resource group is created, HACMP manages the entire resource group and, therefore, all the interdependent resources in it as a single entity. (Note that HACMP coordinates the application recovery and manages the resources in the order that ensures activating all interdependent resources before other resources.) |
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| Question |
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| Why the Min. 2 Ethernet Adapters per client is required? We can configure the HA with the help single adapter also right? |
| Answer |
| We can do that, but when we talk about Hardware dependant, But to have Hardware failure to recover or to aviod need 2 Ethernet adapters. This will provide High availbility as far as Physical Ethernet adapter goes fail/down. |
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| Is it necessary to keep two network interfaces within a server in HACMP configuration? |
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| To reduce Single point of failure in case of Physical Network adapters, we need to have 2 interfaces. |
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| Question |
| Once we configure CAA, can we use regular HACMP design? |
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| Yes, We can use it. |
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| Question |
| Are there any best practices to be followed on the Interaces like FC as well NIC for sensing failure to initiate the failover? |
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| RSCT daemon plays part here to do NIC or FC car failure. |
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| Question |
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| Content of an application monitor? |
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| Monitor Name Monitor Mode Processes to Monitor Process Owner Instance count Stabilization Interval Restart count Restart intercal Action Notify method Cleanup Method Restart Method |
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| Question |
| What does failover time depend on? |
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| Failover time depends on various factors such as Initial System failure detection Service IP address takeover Disk and volume group acquisition Filesystem recovery & mounting Application recovery and startup |
