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InfoScale™ 9.0 Cluster Server Implementation Guide for Oracle - Windows

Last Published: 2025-04-13

Product(s): InfoScale & Storage Foundation (9.0)

Platform: Windows

About the NetApp SnapMirror agent

The NetApp SnapMirror agent monitors the replication state of filer devices. When a failover occurs, the agent reverses the direction of replication. The agent supports the replication modes supported by NetApp. The agent supports asynchronous, semi-synchronous, and synchronous modes of replication. You can set the mode of replication using the SyncMode agent attribute.

NetApp SnapMirror agent functions

The NetApp SnapMirror agent functions are as follows:

Online	If the state of the local filer device is SOURCE, the agent creates a lock file to indicate that the resource can come online. This effectively makes the devices writable for the application. If the state of the local filer is SNAPMIRRORED, the agent attempts to reverse the direction of replication by changing the state of the local filer to SOURCE and that of the original source to SNAPMIRRORED. If the original source filer is down, the agent performs a mirror break-off to enable local write access, if the filer is not already broken off. If the original source returns to life, you must resynchronize the data manually. The online function touches a lock file if read-write access is enabled successfully.
Offline	Removes the lock file. The agent does not perform any filer operations because an offline entry point does not necessarily indicate an intention to give up the devices.
Monitor	Verifies that the lock file exists. If the lock file exists, the monitor function reports the status of the resource as online. If the lock file does not exist, the monitor function reports the status of the resource as offline.
Open	Removes the lock file thereby preventing potential concurrency violation if the group fails over to another node. Note: The agent does not remove the lock file if the agent is started after an hastop -force command.
Clean	Removes the lock file. No filer operations are performed as taking the resource offline does not indicate a pending role swap.

Action function

Use the Action function to perform predefined actions on a resource. To perform an action on a resource, type the following command:

hares -action <SnapMirror_resname> <token> [-actionargs <arg1> ...] [-sys <system>] [-clus <cluster> ]

The following table lists the action supported by the NetAppSnapMirror agent.

Table: Actions supported by NetAppSnapMirror agent

Token for Action	Description
fbsync	Resynchronizes an original source volume with a broken-off volume. After synchronization, the original source volume becomes the target volume. The broken-off volume was initially the target volume, but was broken off as a result of a take over.

Token for Action

Description

fbsync

Resynchronizes an original source volume with a broken-off volume. After synchronization, the original source volume becomes the target volume.

The broken-off volume was initially the target volume, but was broken off as a result of a take over.

To synchronize volumes, type the following at the command prompt:

hares -action SnapMirror_resname fbsync -sys node_name

Where, SnapMirror_resname represents the name of the SnapMirror resource and node_name represents the node on which the service group is online.

Run the action for each SnapMirror resource.

You can also add custom actions for the agents. Refer to the Cluster Server Agent Developer's Guide for more information.

NetApp SnapMirror agent resource type definition and attribute definitions are as follows. This information will assist you during the agent configuration.

NetAppSnapMirror agent resource type definition

NetApp SnapMirror agent is configured as a resource of type NetAppSnapMirror.

type NetAppSnapMirror (
        static keylist SupportedActions = { fbsync }
        static int MonitorInterval = 300
        static int NumThreads = 1
        static i18nstr ArgList[] = { FilerResName, 
        "FilerResName:FilerName", "FilerResName:StorageIP",
        VolumeName, SnapMirrorArguments, SnapMirrorSchedule, 
        AppResName, VisibilityFrequency, SyncMode }
        str FilerResName
        str VolumeName
        str SnapMirrorArguments
        str SnapMirrorSchedule
        str AppResName
								int VisibilityFrequency = 180
								str SyncMode = async
    )

NetAppSnapMirror agent attribute definitions

The following table describes the NetApp SnapMirror agent attributes.

Attribute	Description
FilerResName	Name of the VCS NetAppFiler-type resource in the group. Type and dimension: string-scalar
VolumeName	Name of the filer volume containing the virtual disk. This is the volume that is to be mounted. Define the volume name in the same case as on the filer. Type and dimension: string-scalar
SnapMirrorArguments	Specifies the SnapMirror arguments such as maximum transfer speed and restart mode. The format for this attribute is: <RestartMode> MaxSpeed MaxSpeed is an optional parameter. The RestartMode parameter can have the following values: Always Never Default Setting the RestartMode parameter value to default indicates schedule priority. Default value of RestartMode parameter is 'Default' Example: Always MaxSpeed Type and dimension: string-scalar
SnapMirrorSchedule	Specifies the schedule the destination uses for updating data. Do not assign a value for this attribute if you use SnapManager. The schedule is in the following format: minute hour dayofmonth dayofweek Each field is separated by a space. Refer to the NetApp documentation for more details on the rules for each of these schedule fields. By default, this attribute does not have any value. Type and dimension: string-scalar
AppResName	Name of the resource configured to monitor the application being made highly available. Type and dimension: string-scalar
SyncMode	Specifies the mode of replication for the mirror. This attribute can have the following values: async: Indicates that the mirror should be configured in the asynchronous mode. semi-sync: Indicates that the mirror should be configured in the semi-synchronous mode. sync: Indicates that the mirror should be configured in the synchronous mode. The default is async (asynchronous) mode. Type and dimension: string-scalar
VisibilityFrequency	Specifies how often the source snapshot will be visible on the destination mirror. It controls the value of visibility_interval in the snapmirror.conf file. The default value is 180 seconds. This attribute is applicable only if the mirror is configured in synchronous or semi-synchronous mode. Type and dimension: string-scalar