ASM incorrectly recognize 1TB+ disks on AIX

Recently we decided to consolidate the LUN’s presented to ASM on AIX box.

Prior to consolidation ASM was using 16 x 100G LUN’s. Post consolidation we would only have 2 LUN’s

1 x 1 TB
1 x 600 GB

SYSADMINS created new LUN’s and presented them to AIX server.

Now when I started creating the diskgroup, ASM was not allowing to create diskgroup and throwing following error

ERROR at line 1:
ORA-15018: diskgroup cannot be created
ORA-15099: disk '/dev/rhdiskXX' is larger 
than maximum size of 2097152 MBs

We knew disks are surely not exceeding this size. But when queried v$asm_disk

SQL>select path, total_mb, free_mb from v$asm_disk 
where header_status='CANDIDATE';
-------------- ---------- ----------
/dev/rhdisk10  4293918720 0
/dev/rhdisk11  4293918720 0
/dev/rhdisk12  4293918720 0

It was showing CANDIDATE disks of size 4095TB. Well we even didn’t had that much store in SAN (so no question of sysadmin making any mistake)

Operating system was showing correct disk size

bootinfo -s hdisk10
bootinfo -s hdisk11

After checking for known ASM & AIX bugs, found following

Bug 9495887: ASM RECOGNIZE 1.25 TB DISKS AS 4,095.25 TB DISKS ON AIX.

NOTE: As per this BUG, Versions confirmed as being affected is But in my case it is also seen in

Workaround is to create diskgroup by specifying actual disk size

SQL> create diskgroup fradg external redundancy 
disk '/dev/rhdisk10' size 1000G, '/dev/rhdisk11' size 614400M;


Metalink Doc Ref –

NOTE [ID 9495887.8] – Bug 9495887 – AIX: ASM does not recognize correct diskgroup size for large disks
NOTE [ID 1095202.1] – ASM 11gR2 Incorrectly Recognize Disks (e.g. 1.25 TB) As 4,095.25 TB Disk On AIX.
NOTE [ID 1345562.1] – Master Note For Automatic Storage Management (ASM) For Operating System (OS) Administrators


This entry was posted in Oracle Automatic Storage Management, Oracle Bugs and tagged , , , . Bookmark the permalink.

One Response to ASM incorrectly recognize 1TB+ disks on AIX

  1. Kevin Honde says:


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