Cluster Server 7.4 Agent for EMC SRDF Configuration Guide - Windows

Last Published:
Product(s): InfoScale & Storage Foundation (7.4.1)
Platform: Windows
  1. Introducing the agent for EMC SRDF
    1.  
      About the agent for EMC SRDF
    2.  
      Supported hardware for EMC SRDF
    3.  
      Supported software
    4.  
      Typical EMC SRDF setup in a VCS cluster
    5. EMC SRDF agent functions
      1.  
        About the EMC SRDF agent's online function
      2.  
        About dynamic swap support for the EMC SRDF agent
    6.  
      Installing the agent for EMC SRDF
  2. Configuring the agent for EMC SRDF
    1. Configuration concepts for the EMC SRDF agent
      1.  
        Resource type definition for the EMC SRDF agent
      2. Attribute definitions for the SRDF agent
        1.  
          Required attributes
        2.  
          Optional attributes
        3.  
          Internal attributes
      3.  
        Sample configuration for the EMC SRDF agent
    2. Before you configure the agent for EMC SRDF
      1.  
        About cluster heartbeats
      2.  
        About configuring system zones in replicated data clusters
      3.  
        About preventing split-brain
    3. Configuring the agent for EMC SRDF
      1. Configuring the agent manually in a global cluster
        1.  
          Configuring the Symm heartbeat on each cluster
      2.  
        Configuring the agent manually in a replicated data cluster
      3.  
        Setting the OnlineTimeout attribute for the SRDF resource
      4.  
        Additional configuration considerations for the SRDF agent
  3. Testing VCS disaster recovery support with EMC SRDF
    1. How VCS recovers from various disasters in an HA/DR setup with EMC SRDF
      1.  
        Failure scenarios in global clusters
      2.  
        Failure scenarios in replicated data clusters
    2.  
      Testing the global service group migration
    3.  
      Testing disaster recovery after host failure
    4.  
      Testing disaster recovery after site failure
    5.  
      Performing failback after a node failure or an application failure
    6.  
      Performing failback after a site failure
  4. Setting up fire drill
    1.  
      About fire drills
    2.  
      Fire drill configurations
    3. About the SRDFSnap agent
      1.  
        SRDFSnap agent functions
      2.  
        Resource type definition for the SRDFSnap agent
      3.  
        Attribute definitions for the SRDFSnap agent
      4.  
        About the Snapshot attributes
      5.  
        Sample configuration for a fire drill service group
    4.  
      Additional considerations for running a fire drill
    5.  
      Before you configure the fire drill service group
    6. Configuring the fire drill service group
      1.  
        About the Fire Drill wizard
    7.  
      Verifying a successful fire drill

Setting the OnlineTimeout attribute for the SRDF resource

Set the OnlineTimeout attribute for the SRDF resource so that its entry points do not time out, or they automatically restart if they timed out.

To set the OnlineTimeout attribute

  1. For each SRDF resource in the configuration, use the following formula to calculate an appropriate value for the OnlineTimeout attribute:

    • ndevices represents the number of devices in a device group.

    • dfailovertime represents the time taken to failover a device.

    • ndevicegroups represents the total number of device groups that might fail over simultaneously.

    • The epsilon is for the command instantiation overhead. You can set it to any value based on your setup.

    To set the Online Timeout attribute for a single device group (typically the case for SRDF), multiply the number of devices in the device group with the time taken to failover a device (default = 2 seconds) and add it to the value of epsilon.

    For example: if you have a single device group that consists of 5 devices and the time taken to failover a single device is 50 seconds, set the OnlineTimeout attribute to [(5*50 )+ 10] seconds. The value of the epsilon here is equal to 10 seconds. Thus, the OnlineTimeout attribute is equal to 260 seconds.

    To set the Online Timeout attribute for multiple device groups (currently not supported by SRDF), calculate the OnlineTimeout attribute for all device groups and set the OnlineTimeout attribute to at least the amount of time the largest device group takes to fail over.

  2. If the resulting value seems excessive, divide it by two for every increment in the value of the RestartLimit attribute.

To set the OnlineTimeout attribute using the sigma script

  • Run the sigma script to get recommendations for VCS attribute values.

    C:\Program Files\Veritas\Cluster Server\bin\SRDF\sigma.pl

    Run the script on a node where VCS is running and has the SRDF agent configured.

    The sigma calculator adds 10 seconds to the value for each device group to compensate for the overhead of launching an appropriate symrdf command. Specify another value to the sigma script if the instantiation takes shorter or longer.

    The script runs on the assumption that the VCS program manages all devices in the array. Other operations outside of VCS that hold the array lock might delay the online operation unexpectedly.