Setting up a shared disk secondary server

You set up a shared disk system by configuring the primary server, configuring the SD secondary server, and starting the SD secondary.

Setting up the SD primary server

To set up the primary server:

  1. Set the SDS_TIMEOUT configuration parameter to specify the amount of time in seconds that the primary server waits for a log position acknowledgment to be sent from the SD secondary server.
  2. Configure the alias name of the SD primary server by running the following command:
    onmode -d set SDS primary ha_alias
    The server name that is specified by ha_alias becomes the primary server of the shared disk environment and the source of logs for the SD secondary server.

Setting up the SD secondary server

To set up the SD secondary server:

  1. Set the following configuration parameters in the configuration file.
    • HA_ALIAS: set to define an alias for server-to-server communication in a high-availability cluster.
    • SDS_ENABLE: set to 1 (enable) on the secondary server to enable the shared disk environment.
    • SDS_PAGING: set to the path to two files that are used to hold pages that might be required to be flushed between checkpoints. Each file acts as temporary disk storage for chunks of any page size.
    • SDS_TEMPDBS: set to the temporary dbspace for the SD secondary server that is dynamically created when the server is first started.
    • SDS_LOGCHECK: set to the number of seconds to delay a failover if network communications between the primary and secondary servers is temporarily unavailable.
    • TEMPTAB_NOLOG: set to 1 to prevent logical logging on temporary tables.
    • UPDATABLE_SECONDARY: set to a positive integer if you want to enable client applications to perform update, insert, and delete operations on the secondary server.
  2. Set the following configuration parameters to match those on the primary server:
    • ROOTNAME
    • ROOTPATH
    • ROOTOFFSET
    • ROOTSIZE
    • PHYSFILE
    • LOGFILES
    • LOGSIZE
    • DISK_ENCRYPTION
    You can set other configuration parameters to match those of the primary server except for DBSERVERALIASES, DBSERVERNAME, and SERVERNUM.
  3. Add an entry to the sqlhosts file to identify the primary server:
    #dbservername   nettype   host   servicename   options
     name           protocol  name   port
  4. Start the SD secondary server using the oninit command.

    The SD secondary server processes any open transactions as a fast recovery in quiescent mode. There is increased memory usage in the LGR memory pool during fast recovery.

  5. Examine the online.log file on the secondary server to verify that it completed processing open transactions and is in online mode.
  6. Allow client applications to connect to the SD secondary server.

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