3.4.5.3 Enabling Write Back Flash Cache in a Non-Rolling Basis for Software Versions Lower Than 11.2.3.3.1

You can enable Write Back Flash Cache on a non-rolling basis.

The cell services must be shut down before changing the flashCacheMode attribute. For Oracle Exadata System Software releases prior to 11.2.3.3.1, you must stop cell services when disabling Write Back Flash Cache in a non-rolling manner.

There is a shell script to automate enabling and disabling write back Flash Cache. Refer to My Oracle Support note 1500257.1 for the script and additional information.

Oracle Grid Infrastructure homes and Oracle Database homes must at release 11.2.0.3 BP9 or higher to use write-back Flash Cache. Refer to My Oracle Support note 888828.1 for the minimum release requirements for Oracle Exadata System Software, Oracle Grid Infrastructure home, and Oracle Database home.

1. Log in as the root user to a database node.
2. Shut down the entire cluster.

   # cd $Grid_home/bin
   # ./crsctl stop cluster -all
   

3. Drop the Flash Cache for all cells.

   # dcli -g cell_group -l root cellcli -e DROP FLASHCACHE
   

4. Shut down CELLSRV services.

   # dcli -g cell_group -l root cellcli -e ALTER CELL SHUTDOWN SERVICES CELLSRV
   

5. Confirm that the Flash Cache is in writethrough mode.

   # dcli -g cell_group -l root "cellcli -e list cell detail | grep -i flashcachemode"
   

6. Set the flashCacheMode attribute to writeback.

   # dcli -g cell_group -l root cellcli -e "ALTER CELL FLASHCACHEMODE=writeback"
   

7. Restart cell services.

   # dcli -g cell_group -l root cellcli -e ALTER CELL STARTUP SERVICES CELLSRV
   

8. Re-create the Flash Cache.

   # dcli -g cell_group -l root cellcli -e CREATE FLASHCACHE ALL
   

9. Restart the cluster:

   # cd $Grid_home/bin
   # ./crsctl start cluster -all