Check Oracle ASM disk groups

Check Oracle ASM disk groups

In Oracle 11gR2, a new command is added to check the normally mounted disk groups. This facilitates the maintenance of the database in the asm mode.
 
Applicable in the following scenarios:
 
1: The host server is routinely maintained and the host and Database need to be restarted. If no check is performed, the disk group of the asm instance may fail to be loaded, resulting in a serious accident.
 
For example, if the disk header is damaged, we can check the disk header before restarting to detect problems, timely warnings, and data backup.
 
The test is as follows:
 
Damaged simulated disk Header
[Grid @ 12cdb1 ~] $ Dd if =/dev/zero of =/dev/sde1 bs = 4096 count = 1
1 + 0 records in
1 + 0 records out
4096 bytes (4.1 kB) copied, 0.000932074 s, 4.4 MB/s
[Grid @ 12cdb1 ~] $
[Grid @ 12cdb1 ~] $
[Grid @ 12cdb1 ~] $ Kfed read/dev/sde1 | more
Kfbh. endian: 0; 0x000: 0x00
Kfbh. hard: 0; 0x001: 0x00
Kfbh. type: 0; 0x002: KFBTYP_INVALID
Kfbh. datfmt: 0; 0x003: 0x00
Kfbh. block. blk: 0; 0x004: blk = 0
Kfbh. block. obj: 0; 0x008: file = 0
Kfbh. check: 0; 0x00c: 0x00000000
Kfbh. fcn. base: 0; 0x10: 0x00000000
Kfbh. fcn. wrap: 0; 0x014: 0x00000000
Kfbh. spare1: 0; 0x018: 0x00000000
Kfbh. spare2: 0; 0x01c: 0x00000000
000000000 00000000 00000000 00000000 [...]
Repeat 255 times
KFED-00322: Invalid content encountered during block traversal: [kfbtTraverseBlock] [Invalid OSM block type] [] [0]

Check in the asm instance:

SQL> alter diskgroup dgtest check;

Diskgroup altered.

In this case, we can view the log information in the asm instance:
 
We can see that the red part shows that the disk header information cannot be read. At this time, we have to intervene in the processing.
SQL> alter diskgroup dgtest check
Tue JUNl 22 17:54:47 2014
ERROR: cocould not read the header of disk DGTEST_0000 (0 ).
NOTE: process _ user12084 _ + asm (12084) initiating offline of disk 0.3914034847 (DGTEST_0000) with mask 0x7e in group 2 (DGTEST) without client inserting ing
NOTE: initiating PST update: grp 2 (DGTEST), dsk = 0/0xe94b6e9f, mask = 0x6a, op = clear
Tue JUNl 22 17:54:47 2014
GMON updating disk modes for group 2 at 24 for pid 23 and osid 12084
ERROR: disk 0 (DGTEST_0000) in group 2 (DGTEST) cannot be offlined because the disk group has external redundancy.
Tue JUNl 22 17:54:47 2014
ERROR: too offline disks in PST (grp 2)
Tue JUNl 22 17:54:47 2014
ERROR: Failed to offline disk DGTEST_0000 (0 ).
NOTE: starting check of diskgroup DGTEST
Tue JUNl 22 17:54:48 2014
ASM Health Checker found 1 new failures
Tue JUNl 22 17:54:48 2014
ASM Health Checker found 1 new failures
Tue JUNl 22 17:54:48 2014
GMON checking disk 0 for group 2 at 25 for pid 23 and osid 12084
 
After modifying the disk header, we will check again
No error reported
 
SQL> alter diskgroup dgtest check
Tue JUNl 22 18:07:50 2014
NOTE: starting check of diskgroup DGTEST
Tue JUNl 22 18:07:51 2014
GMON checking disk 0 for group 2 at 26 for pid 23 and osid 12084
Tue JUNl 22 18:07:53 2014
SUCCESS: check of diskgroup DGTEST found no errors
Tue JUNl 22 18:07:53 2014
SUCCESS: alter diskgroup dgtest check

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