Grid Infra – ASM 11.2.0.3 bug on Solaris – slice 2 CANDIDATE

We recently ran into a bug (at least that how I look at it) that is introduced with ASM 11.2.0.3. As of this version, ASM shows slice 2 (the complete disk, starting a cylinder 0 thus inlcuding the VTOC) as an CANDIDATE disk in ASM. In previous versions of ASM (Grid Infra) only slices that started from cylinder 3 (or higher) where shown as CANDIDATE disks in ASM, so you couldn’t accidently select slice 2 to be used for a diskgroup.

In ASM 11.2.0.3 it is possible to add the slice 2 (for example *c0t0d0s2) to an ASM diskgroup while another slice of the same disk, starting at cylinder 3, is already part of the same or even another diskgroup. You can understand what a mess this gives!
Example partition table of solaris disk, where until 11.2.0.3 you would only see partition (slice) 0, starting at cylinder 3 (see MOS note: ASM Does Not Discover Disk on Solaris [ID 368840.1]).

Current partition table (original):
Total disk cylinders available: 13651 + 2 (reserved cylinders)

Part      Tag    Flag     Cylinders         Size            Blocks
  0       root    wm       3 - 13650       49.98GB    (13648/0/0) 104816640
  1 unassigned    wu       0                0         (0/0/0)             0
  2     backup    wu       0 - 13650       49.99GB    (13651/0/0) 104839680
  3 unassigned    wm       0                0         (0/0/0)             0
  4 unassigned    wm       0                0         (0/0/0)             0
  5 unassigned    wm       0                0         (0/0/0)             0
  6 unassigned    wm       0                0         (0/0/0)             0
  7 unassigned    wm       0                0         (0/0/0)             0

ASM (11.2.0.3) discovers the following disks now. Take a good look at the disk number of the MEMBER disks and CANDIDATE disks:

SQL> select path,header_status from v$asm_disk order by 1,2;

PATH                                               HEADER_STATUS
-------------------------------------------------- ---------------
/dev/rdsk/c3t60060E8005492800000049280000319Dd0s0  MEMBER
/dev/rdsk/c3t60060E8005492800000049280000319Dd0s2  CANDIDATE
/dev/rdsk/c3t60060E8005492800000049280000319Ed0s0  MEMBER
/dev/rdsk/c3t60060E8005492800000049280000319Ed0s2  CANDIDATE
/dev/rdsk/c3t60060E8005492800000049280000319Fd0s0  MEMBER
/dev/rdsk/c3t60060E8005492800000049280000319Fd0s2  CANDIDATE
/dev/rdsk/c3t60060E800549280000004928000031A0d0s0  MEMBER
/dev/rdsk/c3t60060E800549280000004928000031A0d0s2  CANDIDATE
/dev/rdsk/c3t60060E800549280000004928000031A6d0s0  MEMBER
/dev/rdsk/c3t60060E800549280000004928000031A6d0s2  CANDIDATE
/dev/rdsk/c3t60060E800549280000004928000031A7d0s0  MEMBER
/dev/rdsk/c3t60060E800549280000004928000031A7d0s2  CANDIDATE
/dev/rdsk/c3t60060E800549280000004928000031A8d0s0  MEMBER
/dev/rdsk/c3t60060E800549280000004928000031A8d0s2  CANDIDATE
/dev/rdsk/c3t60060E800549280000004928000031A9d0s0  MEMBER
/dev/rdsk/c3t60060E800549280000004928000031A9d0s2  CANDIDATE
/dev/rdsk/c3t60060E800549280000004928000031CBd0s0  MEMBER
/dev/rdsk/c3t60060E800549280000004928000031CBd0s2  CANDIDATE

I have created an SR for this problem, but until then you’ll have the following options:

  1. Set the ASM_DISKSTRING parameter to /dev/rdsk/*s0 (or whatever slice you normally use)
  2. Make sure the user grid does not have any privileges on the /dev/rdsk/*s2 devices.

Update 26-02-2013:
Oracle Support finally came back with an answer and a patch. The most important thing is that they agree that this is actually a bug and created a bug (bug nr. 14577881) for it. Support tells me that the problem is “really” fixed in Oracle 12.2 (when even 12.1 is not even released yet ;-)) but they have created a backport request for it. I just got back that the backport is available as a one-off patch downloadable as patch 14577881 for 11.2.0.3.

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