Chapter 1 Planning for Sun Cluster Data Services
This chapter provides planning information and guidelines to install and configure Sun Cluster data services. This chapter contains the following sections.
See the Sun Cluster Concepts Guide for Solaris OS document for conceptual information about data services, resource types, resources, and resource groups.
Sun Cluster software can provide service only for those data services that are either supplied with the Sun Cluster product or are created with the Sun Cluster data services application programming interfaces (APIs)
If your applications are not currently offered as Sun Cluster data services, see the Sun Cluster Data Services Developer's Guide for Solaris OS for information on how to develop highly available data services for applications.
Note –
Sun Cluster software does not have a data service for the sendmail(1M) subsystem. The sendmail subsystem can run on the individual cluster nodes, but the sendmail functionality will not be highly available, including the functionality of mail delivery and mail routing, queuing, or retry.
Configuration Guidelines for Sun Cluster Data Services
This section provides configuration guidelines for Sun Cluster data services.
Identifying Data Service Special Requirements
Identify requirements for all of the data services before you begin Solaris and Sun Cluster installation. Failure to do so might result in installation errors that require that you completely reinstall the Solaris and Sun Cluster software.
For example, the Oracle Parallel Fail Safe/Real Application Clusters Guard option of Sun Cluster Support for Oracle Parallel Server/Real Application Clusters has special requirements for the hostnames that you use in the cluster. Sun Cluster HA for SAP also has special requirements. You must accommodate these requirements before you install Sun Cluster software because you cannot change hostnames after you install Sun Cluster software.Also note that both Sun Cluster Support for Oracle Parallel Server/Real Application Clusters and Sun Cluster HA for SAP are not supported for use in x86 based clusters.
Determining the Location of the Application Binaries
You can install the application software and application configuration files on one of the following locations.
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The local disks of each cluster node – Placing the software and configuration files on the individual cluster nodes provides the following advantage. You can upgrade application software later without shutting down the service.
The disadvantage is that you then have several copies of the software and configuration files to maintain and administer.
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The cluster file system – If you put the application binaries on the cluster file system, you have only one copy to maintain and manage. However, you must shut down the data service in the entire cluster to upgrade the application software. If you can spare a small amount of downtime for upgrades, place a single copy of the application and configuration files on the cluster file system.
See the planning chapter of the Sun Cluster Software Installation Guide for Solaris OS for information on how to create cluster file systems.
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Highly available local file system – Using HAStoragePlus, you can integrate your local file system into the Sun Cluster environment making the local file system highly available. HAStoragePlus provides additional file system capabilities such as checks, mounts, and unmounts enabling Sun Cluster to fail over local file systems. In order to failover, the local file system must reside on global disk groups with affinity switchovers enabled.
See the individual data service guides or Enabling Highly Available Local File Systems for information on how to use the HAStoragePlus resource type.
Verifying the nsswitch.conf File Contents
The nsswitch.conf file is the configuration file for name-service lookups. This file determines the following information.
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which databases within the Solaris environment to use for name-service lookups
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in what order to consult the databases
Some data services require that you direct “group” lookups to “files” first. For these data services, change the “group” line in the nsswitch.conf file so that the “files” entry is listed first. See the documentation for the data service that you plan to configure to determine whether you need to change the “group” line.
See the planning chapter in the Sun Cluster Software Installation Guide for Solaris OS for additional information on how to configure the nsswitch.conf file for the Sun Cluster environment.
Planning the Cluster File System Configuration
Depending on the data service, you might need to configure the cluster file system to meet Sun Cluster requirements. See the documentation for the data service that you plan to configure to determine whether any special considerations apply.
See the planning chapter of the Sun Cluster Software Installation Guide for Solaris OS for information on how to create cluster file systems.
The resource type HAStoragePlus enables you to use a highly available local file system in a Sun Cluster environment configured for failover. See Enabling Highly Available Local File Systems for information on setting up the HAStoragePlus resource type.
Relationship Between Resource Groups and Disk Device Groups
Sun Cluster uses the concept of node lists for disk device groups and resource groups. Node lists are ordered lists of primary nodes, which are potential masters of the disk device group or resource group. Sun Cluster uses a failback policy to determine what happens when a node has been down and then rejoins the cluster, and the rejoining node appears earlier in the node list than the current primary node. If failback is set to True, the device group or resource group will be switched off of the current primary and switched onto the rejoining node, making the rejoining node the new primary.
To ensure high availability of a failover resource group, make the resource group's node list match the node list of associated disk device groups. For a scalable resource group, the resource group's node list cannot always match the device group's node list because, currently, a device group's node list must contain exactly two nodes. For a greater-than-two-node cluster, the node list for the scalable resource group can have more than two nodes.
For example, assume that you have a disk device group, disk-group-1, that has nodes phys-schost-1 and phys-schost-2 in its node list, with the failback policy set to Enabled. Assume that you also have a failover resource group, resource-group-1, which uses disk-group-1 to hold its application data. When you set up resource-group-1, also specify phys-schost-1 and phys-schost-2 for the resource group's node list, and set the failback policy to True.
To ensure high availability of a scalable resource group, make the scalable resource group's node list a superset of the node list for the disk device group. Doing so ensures that the nodes that are directly connected to the disks are also nodes that can run the scalable resource group. The advantage is that, when at least one cluster node connected to the data is up, the scalable resource group runs on that same node, making the scalable services available also.
See the Sun Cluster Software Installation Guide for Solaris OS for information on how to set up disk device groups. See the Sun Cluster Concepts Guide for Solaris OS document for more details on the relationship between disk device groups and resource groups.
Understanding HAStorage and HAStoragePlus
The HAStorage and the HAStoragePlus resource types can be used to configure the following options.
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Coordinate the boot order of disk devices and resource groups by causing the START methods of the other resources in the same resource group that contains the HAStorage or HAStoragePlus resource to wait until the disk device resources become available.
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With AffinityOn set to True, enforce colocation of resource groups and disk device groups on the same node, thus enhancing the performance of disk-intensive data services.
In addition, HAStoragePlus is capable of mounting any global file system found to be in an unmounted state. See Planning the Cluster File System Configuration for more information.
Note –
If the device group is switched to another node while the HAStorage or HAStoragePlus resource is online, AffinityOn has no effect and the resource group does not migrate along with the device group. On the other hand, if the resource group is switched to another node, AffinityOn being set to True causes the device group to follow the resource group to the new node.
See Synchronizing the Startups Between Resource Groups and Disk Device Groups for information about the relationship between disk device groups and resource groups. The SUNW.HAStorage(5) and SUNW.HAStoragePlus(5) man pages provide additional details.
See Enabling Highly Available Local File Systems for procedures for mounting of file systems such as VxFS in a local mode. The SUNW.HAStoragePlus(5) man page provides additional details.
Determining Whether Your Data Service Requires HAStorage or HAStoragePlus
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In cases where a data service resource group has a node list in which some of the nodes are not directly connected to the storage, you must configure HAStorage or HAStoragePlus resources in the resource group and set the dependency of the other data service resources to the HAStorage or HAStoragePlus resource. This requirement coordinates the boot order between the storage and the data services.
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If your data service is disk intensive, such as Sun Cluster HA for Oracle and Sun Cluster HA for NFS, ensure that you perform the following tasks.
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Add a HAStorage or HAStoragePlus resource to your data service resource group.
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Switch the HAStorage or HAStoragePlus resource online.
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Set the dependency of your data service resources to the HAStorage or HAStoragePlus resource.
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Set AffinityOn to True.
When you perform these tasks, the resource groups and disk device groups are colocated on the same node.
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The failback settings must be identical for both the resource group and device group(s).
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If your data service is not disk intensive—such as one that reads all of its files at startup (for example, Sun Cluster HA for DNS)—configuring the HAStorage or HAStoragePlus resource type is optional.
Choosing Between HAStorage and HAStoragePlus
To determine whether to create HAStorage or HAStoragePlus resources within a data service resource group, consider the following criteria.
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Use HAStoragePlus if you are using Sun Cluster 3.0 5/02 or Sun Cluster 3.1. (If you want to integrate any file system locally into a Sun Cluster configured for failover, you must upgrade to Sun Cluster 3.0 5/02 or Sun Cluster 3.1 and use the HAStoragePlus resource type. See Planning the Cluster File System Configuration for more information.)
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Use HAStorage if you are using Sun Cluster 3.0 12/01 or earlier.
Considerations
Use the information in this section to plan the installation and configuration of any data service. The information in this section encourages you to think about the impact your decisions have on the installation and configuration of any data service. For specific considerations for a data service, see the documentation for the data service.
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When using data services that are I/O intensive and that have a large number of disks configured in the cluster, the application may experience delays due to retries within the I/O subsystem during disk failures. An I/O subsystem may take several minutes to retry and recover from a disk failure. This delay can result in Sun Cluster failing over the application to another node, even though the disk may have eventually recovered on its own. To avoid failover during these instances, consider increasing the default probe timeout of the data service. If you need more information or help with increasing data service timeouts, contact your local support engineer.
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For better performance, Install and configure your data service on the cluster nodes with direct connection to the storage.
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Client applications that run on cluster nodes should not map to logical IP addresses of an HA data service. After a failover, these logical IP addresses might no longer exist, leaving the client without a connection.
Node List Properties
You can specify the following three node lists when configuring data services.
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installed_nodes – A property of the resource type for the data service. This property is a list of the cluster node names on which the resource type is installed and enabled to run.
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nodelist – A property of a resource group that specifies a list of cluster node names where the group can be brought online, in order of preference. These nodes are known as the potential primaries or masters of the resource group. For failover services, configure only one resource group node list. For scalable services, configure two resource groups and thus two node lists. One resource group and its node list identifies the nodes on which the shared addresses are hosted. This list is a failover resource group on which the scalable resources depend. The other resource group and its list identifies nodes on which the application resources are hosted. The application resources depend on the shared addresses. Therefore, the node list for the resource group that contains the shared addresses must be a superset of the node list for the application resources.
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auxnodelist – A property of a shared address resource. This property is a list of physical node IDs that identify cluster nodes that can host the shared address but never serve as primary in the case of failover. These nodes are mutually exclusive with the nodes identified in the node list of the resource group. This list pertains to scalable services only. See the scrgadm(1M) man page for details.
Overview of the Installation and Configuration Process
Use the following procedures to install and configure a data service.
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Install the data service packages from the installation medium on which the packages are supplied.
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Sun JavaTM Enterprise System CD
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Sun Java Enterprise System Accessory CD Volume 3
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Install and configure the application to run in the cluster environment.
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Configure the resources and resource groups that the data service uses. When you configure a data service, specify the resource types, resources, and resource groups that the Resource Group Manager (RGM) will manage. The documentation for the individual data services describe these procedures.
Before you install and configure data services, see the Sun Cluster Software Installation Guide for Solaris OS, which includes procedures on how to install the data service software packages and how to configure Internet Protocol Network Multipathing (IP Networking Multipathing) groups that the network resources use.
Note –
You can use SunPlexTM Manager to install and configure the following data services: Sun Cluster HA for Oracle, Sun Cluster HA for Sun Java System Web Server, Sun Cluster HA for Sun Java System Directory Server, Sun Cluster HA for Apache, Sun Cluster HA for DNS, and Sun Cluster HA for NFS. Note that Sun Cluster HA for Oracle and Sun Cluster HA for Apache are supported for use in only SPARC based clusters. See the SunPlex Manager online help for more information.
Installation and Configuration Task Flow
The following table shows a task map of the procedures to install and configure a Sun Cluster failover data service.
Table 1–1 Task Map: Sun Cluster Data Service Installation and Configuration|
Task |
For Instructions, Go to |
|---|---|
|
Install the Solaris and Sun Cluster software | |
|
Set up IP Networking Multipathing groups | |
|
Set up multihost disks | |
|
Plan resources and resource groups |
Appendix C, Data Service Configuration Worksheets and Examples |
|
Decide the location for application binaries, and configure the nsswitch.conf file | |
|
Install and configure the application software |
The appropriate Sun Cluster data services book. |
|
Install the data service software packages |
Sun Cluster Software Installation Guide for Solaris OS or the appropriate Sun Cluster data services book. |
|
Register and configure the data service |
The appropriate Sun Cluster data services book. |
SPARC: Example
The example in this section shows how you might set up the resource types, resources, and resource groups for an Oracle application that has been instrumented to be a highly available failover data service.
The main difference between this example and an example of a scalable data service is that, in addition to the failover resource group that contains the network resources, a scalable data service requires a separate resource group (called a scalable resource group) for the application resources.
The Oracle application has two components, a server and a listener. Sun supplies the Sun Cluster HA for Oracle data service, and therefore these components have already been mapped into Sun Cluster resource types. Both of these resource types are associated with resources and resource groups.
Because this example is a failover data service, the example uses logical hostname network resources, which are the IP addresses that fail over from a primary node to a secondary node. Place the logical hostname resources into a failover resource group, and then place the Oracle server resources and listener resources into the same resource group. This ordering enables all of the resources to fail over as a group.
For Sun Cluster HA for Oracle run to on the cluster, you must define the following objects.
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LogicalHostname resource type – This resource type is built in, and therefore you do not need to explicitly register the resource type.
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Oracle resource types – Sun Cluster HA for Oracle defines two Oracle resource types—a database server and a listener.
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Logical hostname resources – These resources host the IP addresses that fail over in a node failure.
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Oracle resources – You must specify two resource instances for Sun Cluster HA for Oracle—a server and a listener.
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Failover resource group – This container is composed of the Oracle server and listener and logical hostname resources that will fail over as a group.
Tools for Data Service Resource Administration
This section describes the tools that you can use to perform installation and configuration tasks.
The SunPlex Manager Graphical User Interface (GUI)
SunPlex Manager is a web-based tool that enables you to perform the following tasks.
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Install a cluster.
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Administer a cluster.
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Create and configure resources and resource groups.
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Configure data services with the Sun Cluster software.
See the Sun Cluster Software Installation Guide for Solaris OS for instructions on how to use SunPlex Manager to install cluster software. SunPlex Manager provides online help for most administrative tasks.
SPARC: The Sun Cluster Module for the Sun Management Center GUI
The Sun Cluster module enables you to monitor clusters and to perform some operations on resources and resource groups from the Sun Management Center GUI. See the Sun Cluster Software Installation Guide for Solaris OS for information about installation requirements and procedures for the Sun Cluster module. Go to http://docs.sun.com to access the Sun Management Center software documentation set, which provides additional information about Sun Management Center.
The scsetup Utility
The scsetup(1M) utility is a menu-driven interface that you can use for general Sun Cluster administration. You can also use this utility to configure data service resources and resource groups. Select option 2 from the scsetup main menu to launch the Resource Group Manager submenu.
The scrgadm Command
You can use the scrgadm command to register and configure data service resources. See the procedure on how to register and configure your data service in the book for the data service. If, for example, you use Sun Cluster HA for Oracle, see the procedure in Sun Cluster Data Service for Oracle Guide for Solaris OS. Chapter 2, Administering Data Service Resources also contains information on how to use the scrgadm command to administer data service resources. Finally, see the scrgadm(1M) man page for additional information.
Data Service Resource Administration Tasks
The following table lists which tool you can use in addition to the command line for different data service resource administration tasks. See Chapter 2, Administering Data Service Resources for more information about these tasks and for details on how to use the command line to complete related procedures.
Table 1–2 Tools You Can Use for Data Service Resource Administration Tasks|
Task |
SunPlex Manager |
SPARC: Sun Management Center |
The scsetup Utility |
|---|---|---|---|
|
Register a resource type |
Yes |
No |
Yes |
|
Create a resource group |
Yes |
No |
Yes |
|
Add a resource to a resource group |
Yes |
No |
Yes |
|
Bring a resource group online |
Yes |
Yes |
No |
|
Remove a resource group |
Yes |
Yes |
No |
|
Remove a resource |
Yes |
Yes |
No |
|
Switch the current primary of a resource group |
Yes |
No |
No |
|
Disable a resource |
Yes |
Yes |
No |
|
Move the resource group of a disabled resource into the unmanaged state |
Yes |
No |
No |
|
Display resource type, resource group, and resource configuration information |
Yes |
Yes |
No |
|
Change resource properties |
Yes |
No |
No |
|
Clear the STOP_FAILED error flag on resources |
Yes |
No |
No |
|
Add a node to a resource group |
Yes |
No |
No |
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