Changing Failgroup of ASM Disks in Exadata

Posted in: Technical Track

There was a discrepancy in the failgroups of couple of ASM disks in Exadata. In Exadata, the cell name corresponds to the failgroup name. But there were couple of disks with different failgroup names. Using the following plan to rectify the issue online without any downtime:


1) Check disks and their failgroup:

col name format a27
col path format a45

SQL> select path,failgroup,mount_status,mode_status,header_status,state from v$asm_disk order by failgroup, path;

o/100.100.00.000/DBFSDG_CD_09_mycellnet0    mycellNET0             CACHED  ONLINE  MEMBER      NORMAL
o/100.100.00.000/DATA_CD_08_mycellnet0      mycell_NET0             CACHED  ONLINE  MEMBER      NORMAL

2) Drop Disks:

ALTER DISKGROUP DATA DROP DISK  DATA_CD_08_mycellnet0 REBALANCE POWER 32;

3) Wait for rebalanacing to finish

select * from gv$asm_operation;

4) Add the disks to the correct failgroups

ALTER DISKGROUP DATA ADD failgroup mycellNET0 DISK ‘o/100.100.00.000/DATA_CD_08_mycellnet0’ rebalance power 32;

— Wait for rebalance to complete.

5) select * from v$asm_operation;

6) Verify the incorrect failgroup has gone

select name,path,failgroup from v$asm_disk  where failgroup in (‘mycell_NET0’) order by name;

select path,failgroup,mount_status,mode_status,header_status,state from v$asm_disk order by failgroup, path;

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About the Author

I am in love with Oracle blogging since 2007. The blogging coupled with extensive participation in Oracle forums, plus Oracle related speaking engagements, various Oracle certifications, teaching, and working in the trenches with Oracle technologies enabled me to get Oracle ACE award. I was the first ever Pakistani to get that award. From Oracle Open World SF to Foresight 20:20 Perth, I have been expressing my love for Exadata. These days for the last some years, I am loving the data at Pythian, and proudly writing their log buffer carnivals.

1 Comment. Leave new

Alexei Polozov
December 2, 2015 1:30 am

One rebalance should be enough:
ALTER DISKGROUP DATA REBALANCE POWER 0;
ALTER DISKGROUP DATA DROP DISK DATA_CD_08_mycellnet0 ;
ALTER DISKGROUP DATA ADD failgroup mycellNET0 DISK ‘o/100.100.00.000/DATA_CD_08_mycellnet0’;
ALTER DISKGROUP DATA REBALANCE POWER 32;

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