How to fix “DROPPED” griddisk in Cell

You may encounter a situation where a grid disk is in a dropped status in oracle exadata cell storage. This issue can be identified using the following command:

# cellcli -e "list griddisk attributes name,asmmodestatus" |grep DROP
         DATA_CD_00_exa42cel04_m    DROPPED
         ....
         DATA_CD_09_exa42cel04_m    DROPPED
         DATA_CD_10_exa42cel04_m    DROPPED
         DATA_CD_11_exa42cel04_m    DROPPED

Additionally, the ASM alert log may show errors like:

ORA-15032: not all alterations performed
ORA-15410: Disks in disk group DATA do not have equal size.

This error indicates that the grid disks do not have the same size, which is causing issues in the ASM disk group.

Checking Disk Sizes

Run the following SQL query to check the disk sizes:

SQL> select distinct GROUP_NUMBER,OS_MB,TOTAL_MB from v$asm_disk;

GROUP_NUMBER      OS_MB   TOTAL_MB
------------ ---------- ----------
           1     116736     116736
           1     136192     116736
           2      19456      19456

To see detailed disk information within a specific group:

SQL> select path,OS_MB,TOTAL_MB from v$asm_disk where group_number=1 order by 2;

PATH                                                       OS_MB     TOTAL_MB
--------------------------------------------------------- ---------- --------
o/100.xxx.xxx.3;100.xxx.xxx.4/DATA_CD_01_exa42cel05_m     116736     116736
o/100.xxx.xxx.3;100.xxx.xxx.4/DATA_CD_04_exa42cel05_m     136192     116736
....

Checking Grid Disk Sizes in Cell

To verify the grid disk sizes directly in the cell, use:

# cellcli -e list griddisk attributes name, size, diskType,cachedBy,cachingPolicy where asmDiskGroupName='DATA'
         DATA_CD_00_exa42cel05_m    133G    HardDisk        FD_00_exa42cel05_m     default
         DATA_CD_01_exa42cel05_m    114G    HardDisk        FD_02_exa42cel05_m     default
         DATA_CD_02_exa42cel05_m    133G    HardDisk        FD_03_exa42cel05_m     default
         DATA_CD_03_exa42cel05_m    133G    HardDisk        FD_01_exa42cel05_m     default
....

From the above output, it’s clear that DATA_CD_01_exa42cel05_m has a smaller size than the others. To resolve this issue, we need to resize the grid disk.

# cellcli -e alter griddisk DATA_CD_01_exa42cel05_m size=133G

Verifying the Changes

Re-run the cellcli command to ensure all grid disks have the same size:

# cellcli -e list griddisk attributes name, size, diskType,cachedBy,cachingPolicy where asmDiskGroupName='DATA'
DATA_CD_00_exa42cel05_m    133G    HardDisk        FD_00_exa42cel05_m     default
DATA_CD_01_exa42cel05_m    133G    HardDisk        FD_02_exa42cel05_m     default
DATA_CD_02_exa42cel05_m    133G    HardDisk        FD_03_exa42cel05_m     default
....

Final Step: Resizing in ASM

Once the grid disks have been resized, return to ASM and execute:

SQL> ALTER DISKGROUP DATA RESIZE ALL;

This command ensures all disks in the DATA disk group are resized to match the new configuration.

Conclusion

By following these steps, you can resolve the DROPPED status of grid disks in Exadata. Ensuring uniform disk sizes is crucial for ASM disk group stability and avoiding operational disruptions.