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Oracle Solaris Cluster Geographic Edition Data Replication Guide for EMC Symmetrix Remote Data Facility     Oracle Solaris Cluster 4.1
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Document Information

Preface

1.  Replicating Data With EMC Symmetrix Remote Data Facility Software

2.  Administering SRDF Protection Groups

3.  Migrating Services That Use SRDF Data Replication

Detecting Cluster Failure on a System That Uses SRDF Data Replication

Detecting Primary Cluster Failure

Detecting Secondary Cluster Failure

Migrating Services That Use SRDF Data Replication With a Switchover

Validations That Occur Before a Switchover

Results of a Switchover From a Replication Perspective

How to Switch Over an SRDF Protection Group From Primary to Secondary

Forcing a Takeover on a System That Uses SRDF Data Replication

Validations That Occur Before a Takeover

Results of a Takeover From a Replication Perspective

How to Force Immediate Takeover of SRDF Services by a Secondary Cluster

Recovering Services to a Cluster on a System That Uses SRDF Replication

How to Resynchronize and Revalidate the Protection Group Configuration

How to Perform a Failback-Switchover on a System That Uses SRDF Replication

How to Perform a Failback-Takeover on a System That Uses SRDF Replication

Recovering From a Switchover Failure on a System That Uses SRDF Replication

Switchover Failure Conditions

Recovering From Switchover Failure

How to Make the Original Primary Cluster Primary for an SRDF Protection Group

How to Make the Original Secondary Cluster Primary for an SRDF Protection Group

Recovering From an SRDF Data Replication Error

How to Detect Data Replication Errors

How to Recover From an SRDF Data Replication Error

A.  Geographic Edition Properties for SRDF

Index

Recovering Services to a Cluster on a System That Uses SRDF Replication

After a successful takeover operation, the secondary cluster, cluster-newyork, becomes the primary for the protection group and the services are online on the secondary cluster. After the recovery of the original primary cluster, cluster-paris, the services can be brought online again on the original primary by using a process called failback.

Geographic Edition software supports the following two kinds of failback:

If you want to leave the new primary, cluster-newyork, as the primary cluster and the original primary cluster, cluster-paris, as the secondary after the original primary restarts, you can resynchronize and revalidate the protection group configuration without performing a switchover or takeover.

This section contains information about the following topics:

How to Resynchronize and Revalidate the Protection Group Configuration

Use this procedure to resynchronize and revalidate data on the original primary cluster, cluster-paris, with the data on the current primary cluster, cluster-newyork.

Before You Begin

Before you resynchronize and revalidate the protection group configuration, a takeover has occurred on cluster-newyork. The clusters now have the following roles:

  1. Resynchronize the original primary cluster, cluster-paris, with the current primary cluster, cluster-newyork.

    cluster-paris forfeits its own configuration and replicates the cluster-newyork configuration locally. Resynchronize both the partnership and protection group configurations.

    1. On cluster-paris, resynchronize the partnership.
      phys-paris-1# geops update partnershipname
      partnershipname

      Specifies the name of the partnership


      Note - You need to perform this step only once, even if you are resynchronizing multiple protection groups.


      For more information about synchronizing partnerships, see Resynchronizing a Partnership in Oracle Solaris Cluster Geographic Edition System Administration Guide.

    2. On cluster-paris, resynchronize each protection group.

      Because the role of the protection group on cluster-newyork is primary, this step ensures that the role of the protection group on cluster-paris is secondary.

      phys-paris-1# geopg update protectiongroupname
      protectiongroupname

      Specifies the name of the protection group

      For more information about synchronizing protection groups, see Resynchronizing an SRDF Protection Group.

  2. On cluster-paris, validate the cluster configuration for each protection group.
    phys-paris-1# geopg validate protectiongroupname 
    protectiongroupname

    Specifies a unique name that identifies a single protection group

    For more information, see How to Validate an SRDF Protection Group.

  3. On cluster-paris, activate each protection group.

    Because the protection group on cluster-paris has a role of secondary, the geopg start command does not restart the application on cluster-paris.

    phys-paris-1# geopg start -n -e local protectiongroupname
    -e local

    Specifies the scope of the command.

    By specifying a local scope, the command operates on the local cluster only.

    -n

    Specifies that data replication should not be used for this protection group. If this option is omitted, data replication starts at the same time as the protection group.

    protectiongroupname

    Specifies the name of the protection group.

    Because the protection group has a role of secondary, the data is synchronized from the current primary, cluster-newyork, to the current secondary, cluster-paris.

    For more information about the geopg start command, see How to Activate an SRDF Protection Group.

  4. Confirm that the protection group configuration is OK.

    First, confirm that the state of the protection group on cluster-newyork is OK. The protection group has a local state of OK when the SRDF device groups on cluster-newyork have a Synchronized SRDF pair state.

    phys-newyork-1# geoadm status

    Refer to the Protection Group section of the output.

    Next, confirm that all resources in the replication resource group, protectiongroupname-rep-rg, report a status of OK.

    phys-newyork-1# clresource status -g protectiongroupname-rep-rg

How to Perform a Failback-Switchover on a System That Uses SRDF Replication

Use this procedure to restart an application on the original primary cluster, cluster-paris, after the data on this cluster has been resynchronized with the data on the current primary cluster, cluster-newyork.


Note - The failback procedures apply only to clusters in a partnership. You need to perform the following procedure only once per partnership.


Before You Begin

Before you perform a failback-switchover, a takeover has occurred on cluster-newyork. The clusters have the following roles:

  1. Ensure that the RDF1 role is not in the Split state on cluster-paris.

    This task is necessary to finish recovery if the cluster had experienced a complete site failure.

    1. On cluster-paris, the original primary, display the role and state of the data replication.
      phys-paris-1# symrdf -g devicegroup query
    2. If the role is RDF1 and is in the Split state, fail over the device group.
      phys-paris-1# symrdf -g devicegroup failover
  2. Resynchronize the original primary cluster, cluster-paris, with the current primary cluster, cluster-newyork.

    cluster-paris forfeits its own configuration and replicates the cluster-newyork configuration locally. Resynchronize both the partnership and protection group configurations.

    1. On cluster-paris, resynchronize the partnership.
      phys-paris-1# geops update partnershipname
      partnershipname

      Specifies the name of the partnership


      Note - You need to perform this step only once per partnership, even if you are performing a failback-switchover for multiple protection groups in the partnership.


      For more information about synchronizing partnerships, see Resynchronizing a Partnership in Oracle Solaris Cluster Geographic Edition System Administration Guide.

    2. Determine whether the protection group on the original primary cluster, cluster-paris, is active.
      phys-paris-1# geoadm status
    3. If the protection group on the original primary cluster is active, stop it.
      phys-paris-1# geopg stop -e local protectiongroupname
    4. Verify that the protection group is stopped.
      phys-paris-1# geoadm status
    5. On cluster-paris, resynchronize each protection group.

      Because the local role of the protection group on cluster-newyork is now primary, this steps ensures that the role of the protection group on cluster-paris becomes secondary.

      phys-paris-1# geopg update protectiongroupname
      protectiongroupname

      Specifies the name of the protection group

      For more information about synchronizing protection groups, see Resynchronizing an SRDF Protection Group.

  3. On cluster-paris, validate the cluster configuration for each protection group.

    Ensure that the protection group is not in an error state. A protection group cannot be started when it is in a error state.

    phys-paris-1# geopg validate protectiongroupname 
    protectiongroupname

    Specifies a unique name that identifies a single protection group

    For more information, see How to Validate an SRDF Protection Group.

  4. On cluster-paris, activate each protection group.

    Because the protection group on cluster-paris has a role of secondary, the geopg start command does not restart the application on cluster-paris.

    phys-paris-1# geopg start -e local protectiongroupname
    -e local

    Specifies the scope of the command.

    By specifying a local scope, the command operates on the local cluster only.

    protectiongroupname

    Specifies the name of the protection group.


    Note - Do not use the -n option when performing a failback-switchover because the data needs to be synchronized from the current primary, cluster-newyork, to the current secondary, cluster-paris.


    Because the protection group has a role of secondary, the data is synchronized from the current primary, cluster-newyork, to the current secondary, cluster-paris.

    For more information about the geopg start command, see How to Activate an SRDF Protection Group.

  5. Confirm that the data is completely synchronized.

    The data is completely synchronized when the state of the protection group on cluster-newyork is OK. The protection group has a local state of OK when the SRDF device groups on cluster-newyork have a Synchronized RDF pair state.

    To confirm that the state of the protection group on cluster-newyork is OK, use the following command:

    phys-newyork-1# geoadm status

    Refer to the Protection Group section of the output.

  6. On both partner clusters, ensure that the protection group is activated.
    # geoadm status
  7. On either cluster, perform a switchover from cluster-newyork to cluster-paris for each protection group.
    # geopg switchover [-f] -m cluster-paris protectiongroupname

    For more information, see How to Switch Over an SRDF Protection Group From Primary to Secondary.

    cluster-paris resumes its original role as primary cluster for the protection group.

  8. Ensure that the switchover was performed successfully.

    Verify that the protection group is now primary on cluster-paris and secondary on cluster-newyork and that the state for “Data replication” and “Resource groups” is OK on both clusters.

    # geoadm status

    Check the runtime status of the application resource group and data replication for each SRDF protection group.

    # clresourcegroup status -v protectiongroupname

    Refer to the Status and Status Message fields that are presented for the data replication device group you want to check. For more information about these fields, see Table 2-1.

    For more information about the runtime status of data replication, see Checking the Runtime Status of SRDF Data Replication.

How to Perform a Failback-Takeover on a System That Uses SRDF Replication

Use this procedure to restart an application on the original primary cluster, cluster-paris and use the current data on the original primary cluster. Any updates that occurred on the secondary cluster, cluster-newyork, while it was acting as primary are discarded.

The failback procedures apply only to clusters in a partnership. You need to perform the following procedure only once per partnership.


Note - To resume using the data on the original primary, cluster-paris, you must not have replicated data from the new primary, cluster-newyork, to the original primary cluster, cluster-paris, at any point after the takeover operation on cluster-newyork. To prevent data replication between the new primary and the original primary, you must have used the -n option whenever you used the geopg start command.


Before You Begin

Ensure that the clusters have the following roles:

  1. Ensure that the RDF1 role is not in the Split state on cluster-paris.

    This task is necessary to finish recovery if the cluster had experienced a complete site failure.

    1. On cluster-paris, display the role and state of the data replication.
      phys-paris-1# symrdf -g devicegroup query
    2. If the role is RDF1 and is in the Split state, fail over the device group.
      phys-paris-1# symrdf -g devicegroup failover
  2. Resynchronize the original primary cluster, cluster-paris, with the original secondary cluster, cluster-newyork.

    cluster-paris forfeits its own configuration and replicates the cluster-newyork configuration locally.

    1. On cluster-paris, resynchronize the partnership.
      phys-paris-1# geops update partnershipname
      partnershipname

      Specifies the name of the partnership


      Note - You need to perform this step only once per partnership, even if you are performing a failback-takeover for multiple protection groups in the partnership.


      For more information about synchronizing partnerships, see Resynchronizing a Partnership in Oracle Solaris Cluster Geographic Edition System Administration Guide.

    2. Determine whether the protection group on the original primary cluster, cluster-paris, is active.
      phys-paris-1# geoadm status
    3. If the protection group on the original primary cluster is active, stop it.
      phys-paris-1# geopg stop -e local protectiongroupname
    4. Verify that the protection group is stopped.
      phys-paris-1# geoadm status
    5. On cluster-paris, resynchronize each protection group.

      Because the local role of the protection group on cluster-newyork is now primary, this steps ensures that the role of the protection group on cluster-paris becomes secondary.

      phys-paris-1# geopg update protectiongroupname
      protectiongroupname

      Specifies the name of the protection group

      For more information about resynchronizing protection groups, see How to Resynchronize a Protection Group.

  3. On cluster-paris, validate the configuration for each protection group.

    Ensure that the protection group is not in an error state. A protection group cannot be started when it is in a error state.

    phys-paris-1# geopg validate protectiongroupname 
    protectiongroupname

    Specifies a unique name that identifies a single protection group

    For more information, see How to Validate an SRDF Protection Group.

  4. On cluster-paris, activate each protection group in the secondary role without data replication.

    Because the protection group on cluster-paris has a role of secondary, the geopg start command does not restart the application on cluster-paris.


    Note - You must use the -n option which specifies that data replication should not be used for this protection group. If this option is omitted, data replication starts at the same time as the protection group.


    phys-paris-1# geopg start -e local -n protectiongroupname
    -e local

    Specifies the scope of the command.

    By specifying a local scope, the command operates on the local cluster only.

    -n

    Specifies that data replication should not be used for this protection group. If this option is omitted, data replication starts at the same time as the protection group.

    protectiongroupname

    Specifies the name of the protection group

    For more information, see How to Activate an SRDF Protection Group.

    Replication from cluster-newyork to cluster-paris is not started because the -n option is used on cluster-paris.

  5. On cluster-paris, initiate a takeover for each protection group.
    phys-paris-1# geopg takeover [-f] protectiongroupname
    -f

    Forces the command to perform the operation without your confirmation

    protectiongroupname

    Specifies the name of the protection group

    For more information about the geopg takeover command, see How to Force Immediate Takeover of SRDF Services by a Secondary Cluster.

    The protection group on cluster-paris now has the primary role, and the protection group on cluster-newyork has the role of secondary. The application services are now online on cluster-paris.

  6. On cluster-newyork, activate each protection group.

    At the end of step 4, the local state of the protection group on cluster-newyork is Offline. To start monitoring the local state of the protection group, you must activate the protection group on cluster-newyork.

    Because the protection group on cluster-newyork has a role of secondary, the geopg start command does not restart the application on cluster-newyork.

    phys-newyork-1# geopg start -e local [-n] protectiongroupname
    -e local

    Specifies the scope of the command.

    By specifying a local scope, the command operates on the local cluster only.

    -n

    Prevents the start of data replication at protection group startup.

    If you omit this option, the data replication subsystem starts at the same time as the protection group.

    protectiongroupname

    Specifies the name of the protection group.

    For more information about the geopg start command, see How to Activate an SRDF Protection Group.

  7. Ensure that the takeover was performed successfully.

    Verify that the protection group is now primary on cluster-paris and secondary on cluster-newyork and that the state for “Data replication” and “Resource groups” is OK on both clusters.

    # geoadm status

    Note - If you used the -n option in step 5 to prevent data replication from starting, the “Data replication” status will not be in the OK state.


    Check the runtime status of the application resource group and data replication for each SRDF protection group.

    # clresourcegroup status -v protectiongroupname

    Refer to the Status and Status Message fields that are presented for the data replication device group you want to check. For more information about these fields, see Table 2-1.

    For more information about the runtime status of data replication, see Checking the Runtime Status of SRDF Data Replication.