Review “Upgrading from a previous version” for steps common to all database migrations.
Synchronize and shutdown multiplex all query nodes. See “Synchronize and shutdown multiplex query nodes” for more information.
Migrate local stores, if necessary. This step is only required if you created local stores for your 12.x multiplex query nodes. See “Migrate your local stores” for more information.
Run sp_iqcheckdb to check the validity of your 12.x databases. Repair any index and allocation problems. See “Verify the 12.x databases before migration” for more information.
Start the multiplex write server in single node mode. See “Start the multiplex write server in single node mode” for more information.
Shutdown your 12.x server and backup your database. See “Shutdown your 12.x server” for more information.
Run iqunload with the appropriate parameters to migrate your databases. See “Use iqunload to migrate your database” for more information.
Use the -iqro 1 -iqmpx_sn 1 switches to start the writer in READONLY mode. See “Start the 15.1 migrated database”.
Run sp_iqcheckdb to verify your migrated databases, then backup the databases. See “Verify the migrated databases” for more information.
Synchronize the secondary nodes from the coordinator node. See “Manually synchronize the secondary nodes” for more information.
Start the secondary nodes, then import the schema and data for the local stores into the coordinator. See “Start the secondary nodes” for more information.
Set the failover mode for the failover node. See “Set the failover node” for more information.
Complete any necessary post-migration tasks. See “Post-migration tasks” for more information.
