Best practices for asynchronous GLVM deployment

Consider the following best practices for asynchronous Graphical Logical Volume Manager (GLVM) deployment.

  • Configure the value of the RPV level I/O timeout parameter by using the chdev command to avoid any network latency problems that are related to the I/O timeout value. You can modify this timeout parameter when the rpv disk is in the defined state. The default value of this parameter is 180 seconds.
  • In a stand-alone GLVM environment, you must ensure that all the backup disks in the secondary sites are in an active state before you bring the volume group online. During the online recovery of the volume group, if the RPV device driver detects that the RPV server is not online to perform a specific asynchronous I/O operation, the RPV device driver updates in the cache disk about the failed request. The I/O operations continue running synchronously. If you want to revert to asynchronous mirroring after you rectify the problem, you can use the chmp command.
  • After a site fails, the state of asynchronous mirroring in secondary site might be inactive. After you integrate the secondary site again with the primary site, the mirror pool must be converted to asynchronous mirroring to continue asynchronous mirroring deployment.
  • Monitor regularly whether the asynchronous mirroring state of the GLVM is active by using the lsmp command. The rpvstat –A command shows the statistics and states of asynchronous mirroring.
  • Monitor the asynchronous I/O operations and number of active connections in the GLVM environment regularly. The rpvstat -n command displays details of about a specific network. The rpvstat -A command displays details about asynchronous I/O operations. The rpvstat -C command displays statistics about the cache logical volumes.
  • For better performance, ensure that the disk driver parameters of the storage device that is deployed in your environment is configured correctly.