How to disassemble a DB2 HADR/Cluster into a Standard DB2 database

There is tons of information about setting up High availability for IBM DB2 database but not a lot about taking it apart. Probably is not something you need to do everyday but I had to change the landscape of one of my environments and this is how I achieved it.

• First thing you need to do is to make sure the database you want to keep is set as primary
  • You can check this via lssam or by checking the database config parameter “HADR database role”

db2 get db cfg for <instance> | grep “HADR database role”
HADR database role                                      = PRIMARY

• Stop SAP
  • Ermm, stopsap

• Stop HADR and deactivate both databases (do not stop the database manager on primary)
  • On Standby
    • Deactivate ->  db2 deactivate db <instance>
    • Stop HADR -> db2 stop hadr on db <instance>
    • db2stop
  • On Primary
    • Stop HADR -> db2 stop hadr on db <instance>
    • Deactivate -> db2 deactivate db <instance>

• list your HADR parameters
  • db2 get db cfg for <instance> | grep HADR

HADR database role                                      = STANDARD
HADR local host name                                  (HADR_LOCAL_HOST) = <primary_host>
HADR local service name                             (HADR_LOCAL_SVC) = <SID>_HADR_1
HADR remote host name                              (HADR_REMOTE_HOST) = <standby_host>
HADR remote service name                          (HADR_REMOTE_SVC) = <SID>_HADR_2
HADR instance name of remote server         (HADR_REMOTE_INST) = db2<sid>
HADR timeout value                                      (HADR_TIMEOUT) = 120
HADR target list                                            (HADR_TARGET_LIST) =
HADR log write synchronization mode           (HADR_SYNCMODE) = NEARSYNC
HADR spool log data limit (4KB)                    (HADR_SPOOL_LIMIT) = AUTOMATIC(982800)
HADR log replay delay (seconds)                 (HADR_REPLAY_DELAY) = 0
HADR peer window duration (seconds)         (HADR_PEER_WINDOW) = 300

• On the primary database disable the HADR parameters using…

db2 update db cfg for <instance> using HADR_LOCAL_HOST NULL

db2 update db cfg for <instance> using HADR_LOCAL_SVC NULL

db2 update db cfg for <instance> using HADR_REMOTE_HOST NULL

db2 update db cfg for <instance> using HADR_REMOTE_SVC NULL

db2 update db cfg for <instance> using HADR_REMOTE_INST NULL

stop the database manager and start it again. (db2stop/db2start)

• delete the high availability configuration (very important!!)
  • db2haicu -delete

• uninstall the SAMP cluster in both database hosts (from root)

./opt/IBM/tsamp/sam/uninst/uninstallSAM

• update your SAP profile parameters to point to the single host instead of the virtual host
  • parameters SAPDBHOST and j2ee/dbhost

• update your db2cli.ini to point to the single hosts instead of the virtual host
  • parameter Hostname

• start your DB2 instance normally
  • db2start
  • db2 activate db <instance>

• start your SAP system
  • startsap

Now you have a standalone database and you can decommission your standby database host!!

Love to hear your comments.