Cluster Server 7.4 Agent for EMC SRDF Configuration Guide - Windows
- Introducing the agent for EMC SRDF
- Configuring the agent for EMC SRDF
- Testing VCS disaster recovery support with EMC SRDF
- How VCS recovers from various disasters in an HA/DR setup with EMC SRDF
- Testing the global service group migration
- Testing disaster recovery after host failure
- Testing disaster recovery after site failure
- Performing failback after a node failure or an application failure
- Performing failback after a site failure
- Setting up fire drill
EMC SRDF agent functions
The VCS agent for SRDF monitors and manages the state of replicated Symmetrix devices that are attached to VCS nodes.
The agent performs the following functions:
Table: Agent functions
Function | Description |
|---|---|
online | This operation makes the devices writable for the application. If one or more devices are in the write-disabled (WD) state, the agent runs the symrdf command to enable read-write access to the devices. If the state of all local devices in an RDF1 type device group is read-write enabled (RW) and the replication link is in the Consistent or Synchronized state, the agent creates a lock file on the local host. The lock file indicates that the resource is online. It checks the dynamic swap capability of the array and individual devices. It also creates the swap lock file if the device group is capable of role swap. See About dynamic swap support for the EMC SRDF agent. |
offline | Removes the lock file on the local host. The agent does not run any SRDF commands because taking the resource offline is not indicative of the intention to give up the devices. |
monitor | Verifies that the lock file exists. If the lock file exists, the monitor entry point reports the status of the resource as online. If the lock file does not exist, the monitor entry point reports the status of the resource as offline. |
open | Removes the lock file on the host where the entry point is called. This operation prevents potential concurrency violation if the service group fails over to another node. Note: The agent does not remove the lock file if the agent was started after running the following command: hastop<-all | -local> -force |
clean | Determines if it is safe to fault the resource if the online entry point fails or times out. |
info | Reports the device state to the VCS interface. This entry point can be used to verify the device state and to monitor dirty track trends. |
action/update | Performs a symrdf update action from the R2 side to merge any dirty tracks from the R2 to the R1. |
action/PreSwitch | Ensures that the remote site cluster can come online during a planned failover within a GCO configuration. The VCS engine on the remote cluster invokes the PreSwitch action on all the resources of the remote site during a planned failover using the hagrp -switch command. For this, the PreSwitch Action attribute must be set to 1. The option -nopre indicates that the VCS engine must switch the servicegroup regardless of the value of the PreSwitch service group attribute. If running the PreSwitch action fails, the failover should not occur. This minimizes the application downtime and data loss. For more information on the PreSwitch action and the PreSwitch feature in the VCS engine, refer to the Cluster Server Administrator's Guide. |
close | Deletes the swap lock file. |
Attr_changed | Monitors the changes in the attribute GrpName. If the device group name is changed, the instructions are logged for the changes to be effective. |
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