ASM Diskgroup With Normal Redundancy Dismounts After Failure of Only One Failure Group (Oracle recommends having a Quorum Disk or Third Failrue Group)

(Doc ID 2344251.1)

Last updated on JANUARY 05, 2018

Applies to:

Oracle Database - Enterprise Edition - Version 12.1.0.2 and later
Information in this document applies to any platform.

Symptoms

On a diskgroup with normal redundancy with two failure groups, if multiple disks on one failure group fails, the diskgroup gets dismounted.
The diskgroup with normal redundancy and two fail groups should survive multiple disk failures if the failures occur in one failure group

The expected behavior with normal redundancy is offlining the disks on the problem failure group, but the diskgroup gets dismounted:


asm alert.log:

Mon Jul 24 18:30:36 2017
WARNING: Write Failed. group:3 disk:6 AU:69986 offset:471040 size:4096
path:/dev/mapper/asm_bsstrac_data_3parbd01p1
incarnation:0xe96b44df synchronous result:'I/O error'
subsys:System krq:0x7fcf4b7b1948 bufp:0x7ed67000 osderr1:0x69b5 osderr2:0x0
IO elapsed time: 0 usec Time waited on I/O: 0 usec
NOTE: cache initiating offline of disk 6 group RACDATA
NOTE: process _lgwr_+asm4 (18363) initiating offline of disk 6.3916121311 (RACDATA_0006) with mask 0x7e in group 3 (RACDATA) with client assisting
NOTE: checking PST: grp = 3
Mon Jul 24 18:30:36 2017
GMON checking disk modes for group 3 at 83 for pid 17, osid 18363
Mon Jul 24 18:30:36 2017
NOTE: checking PST for grp 3 done.
NOTE: initiating PST update: grp 3 (RACDATA), dsk = 6/0xe96b44df, mask = 0x6a, op = clear
Mon Jul 24 18:30:36 2017
GMON updating disk modes for group 3 at 84 for pid 17, osid 18363
WARNING: Write Failed. group:3 disk:6 AU:1 offset:1044480 size:4096
path:/dev/mapper/asm_bsstrac_data_3parbd01p1
incarnation:0xe96b44df synchronous result:'I/O error'
subsys:System krq:0x7f7a896c1598 bufp:0x7f7a896c2000 osderr1:0x69b5 osderr2:0x0
IO elapsed time: 0 usec Time waited on I/O: 0 usec
WARNING: Write Failed. group:3 disk:7 AU:1 offset:1044480 size:4096
path:/dev/mapper/asm_bsstrac_data_3parbd02p1
incarnation:0xe96b44e0 synchronous result:'I/O error'
subsys:System krq:0x7f7a896c1178 bufp:0x7f7a896d8000 osderr1:0x69b5 osderr2:0x0
IO elapsed time: 0 usec Time waited on I/O: 0 usec
WARNING: Write Failed. group:3 disk:8 AU:1 offset:1044480 size:4096
path:/dev/mapper/asm_bsstrac_data_3parbd03p1
incarnation:0xe96b44de synchronous result:'I/O error'
subsys:System krq:0x7f7a896c0d58 bufp:0x7f7a896d6000 osderr1:0x69b5 osderr2:0x0
IO elapsed time: 0 usec Time waited on I/O: 0 usec
WARNING: found another non-responsive disk 6.3916121311 (RACDATA_0006) that will be offlined
WARNING: found another non-responsive disk 7.3916121312 (RACDATA_0007) that will be offlined
WARNING: found another non-responsive disk 8.3916121310 (RACDATA_0008) that will be offlined
WARNING: GMON has insufficient disks to maintain consensus for group 3. Minimum required is 2: updating 1 PST copies from a total of 2.
WARNING: force dismounting DG grp=3 for failing consensus
ERROR: GMON failed to obtain a quorum of supporting disks in group 3

 

Cause

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