When performing maintenance on Exadata Storage Servers, it may be necessary to power down or reboot the cell. If Exadata Storage Server is to be shut down when one or more databases are running, then verify that taking Exadata Storage Server offline will not impact Oracle ASM disk group and database availability. The ability to take Exadata Storage Server offline without affecting database availability depends on the level of Oracle ASM redundancy used on the affected disk groups, and the current status of disks in other Exadata Storage Servers that have mirror copies of data as Exadata Storage Server to be taken offline.
Use the following procedure describes to power down Exadata Storage Server.
CellCLI> LIST GRIDDISK ATTRIBUTES name WHERE asmdeactivationoutcome != 'Yes'
If any grid disks are returned, then it is not safe to take Exadata Storage Server offline because proper Oracle ASM disk group redundancy will not be maintained. Taking Exadata Storage Server offline when one or more grid disks are in this state will cause Oracle ASM to dismount the affected disk group, causing the databases to shut down abruptly.
CellCLI> ALTER GRIDDISK ALL INACTIVE
The preceding command completes once all disks are inactive and offline.
CellCLI> LIST GRIDDISK WHERE STATUS != 'inactive'
If all grid disks are INACTIVE, then Exadata Storage Server can be shut down without affecting database availability.
CellCLI> ALTER GRIDDISK ALL ACTIVE
When the grid disks become active, Oracle ASM automatically synchronizes the grid disks to bring them back into the disk group.
CellCLI> LIST GRIDDISK ATTRIBUTES name, asmmodestatus
Wait until asmmodestatus is ONLINE or UNUSED for all grid disks. For example:
DATA_CD_00_dm01cel01 ONLINE DATA_CD_01_dm01cel01 SYNCING DATA_CD_02_dm01cel01 OFFLINE DATA_CD_02_dm02cel01 OFFLINE DATA_CD_02_dm03cel01 OFFLINE DATA_CD_02_dm04cel01 OFFLINE DATA_CD_02_dm05cel01 OFFLINE DATA_CD_02_dm06cel01 OFFLINE DATA_CD_02_dm07cel01 OFFLINE DATA_CD_02_dm08cel01 OFFLINE DATA_CD_02_dm09cel01 OFFLINE DATA_CD_02_dm10cel01 OFFLINE DATA_CD_02_dm11cel01 OFFLINE
Oracle ASM synchronization is complete only when all grid disks show asmmodestatus=ONLINE or asmmodestatus=UNUSED. Before taking another Exadata Storage Server offline, Oracle ASM synchronization must complete on the restarted Exadata Storage Server. If synchronization is not complete, the check performed on another Exadata Storage Server will fail. For example:
CellCLI> list griddisk attributes name where asmdeactivationoutcome != 'Yes' DATA_CD_00_dm01cel02 "Cannot de-activate due to other offline disks in the diskgroup" DATA_CD_01_dm01cel02 "Cannot de-activate due to other offline disks in the diskgroup" DATA_CD_02_dm01cel02 "Cannot de-activate due to other offline disks in the diskgroup" DATA_CD_03_dm01cel02 "Cannot de-activate due to other offline disks in the diskgroup" DATA_CD_04_dm01cel02 "Cannot de-activate due to other offline disks in the diskgroup" DATA_CD_05_dm01cel02 "Cannot de-activate due to other offline disks in the diskgroup" DATA_CD_06_dm01cel02 "Cannot de-activate due to other offline disks in the diskgroup" DATA_CD_07_dm01cel02 "Cannot de-activate due to other offline disks in the diskgroup" DATA_CD_08_dm01cel02 "Cannot de-activate due to other offline disks in the diskgroup" DATA_CD_09_dm01cel02 "Cannot de-activate due to other offline disks in the diskgroup" DATA_CD_10_dm01cel02 "Cannot de-activate due to other offline disks in the diskgroup" DATA_CD_11_dm01cel02 "Cannot de-activate due to other offline disks in the diskgroup"