ETERNUS SF Express V15.0 Operation Guide

4.4.10 Executing remote copy (DR configuration)

This section describes remote copy (or Extended Remote Advanced Copy) in a Disaster Recovery system configuration.

For details on the operation procedures, refer to "Perform the Advanced Copy" in the "ETERNUS SF Web Console Guide".

Against disasters, remote copy in a DR configuration executes copy within ETERNUS Disk storage systems at both local site and remote site. If a disaster occurs, ETERNUS Disk storage system at local site is switched to ETERNUS Disk storage system at remote site to continue the system operation.

The remote copy has three types of operation modes. Select an operation mode according to the operation form. For more specific information about operation mode, refer to "A.7 Remote Advanced Copy (REC)".

In a configuration that data transfer length is long or a configuration that transfer path includes WAN, data transfer time could be long. In synchronous transfer mode, response to input/output request from the business server could not be returned within response time. Using the asynchronous transfer mode can reduce the effect of delaying response to input/output request from the business server.

For DR configuration, asynchronous transfer mode is recommended.

Figure 4.8 DR configuration diagram

4.4.10.1 Operation procedure for fault occurrence on ETERNUS Disk storage system

If Advanced Copy cannot be continued due to hardware fault, the ETERNUS Disk storage system automatically suspends Advanced Copy.
In addition, remote copy sessions are automatically turned to "Error Suspend" or "Hardware Suspend".

• In the case that "Hardware Suspend" occurs

  1. If all the following conditions are fulfilled, execute "Suspend" operation to suspend the remote copy session.

     • Transfer mode is "Synchronous".

     • Copy status is equivalent.

     • Split mode is "Manual Split".

  2. Remove the error.

  3. If Recovery mode is "Manual Recovery", execute "Suspend" operation to suspend the copy session. After that, execute "Resume" operation to recover the remote copy session.

     Point

     If Recovery mode is "Automatic Recovery", remote copy sessions are automatically recovered, so that no operation is required.

     
     

• In the case that ETERNUS Disk storage system at local site causes "Error Suspend"

  1. Configure the access volume to ETERNUS Disk storage system at remote site from the Management Server.

  2. Select the remote copy session in the target ETERNUS Disk storage system to suspend or cancel, and then execute the forcibly cancel suspend or forcibly suspend.

  In this way, you can access from the operation server to the volumes.

  
  

• In the case that ETERNUS Disk storage system at remote site causes "Error Suspend"

  1. Recover ETERNUS Disk storage system in which the copy destination volume exists.

  2. Execute "Resume" operation to recover the remote copy session.