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This article is about how to deal with ASM Disk loss. Xiaobian thinks it is quite practical, so share it with everyone for reference. Let's follow Xiaobian and have a look.

Phenomenon:

ASM disks are lost after a forced restart of a virtual machine as follows:

[root@ora01 disks]# oracleasm status

Checking if ASM is loaded: yes

Checking if /dev/oracleasm is mounted: yes

ASM driver loading normal

[root@ora01 disks]# oracleasm listdisks -----No ASM disks listed

Go to/dev/oracleasm/disks

[root@ora01 disks]# ls -ltr

total 0

Could not find disk file.

Of course, the corresponding disk group cannot be mounted normally, and the database cannot be started normally.

Solution:

View via dump ASM disk header

[root@ora01 ~]# dd if=/dev/xvdc1 of=./ d1 bs=4K count=1

1+0 records in

1+0 records out

4096 bytes (4.1 kB) copied, 0.000977898 s, 4.2 MB/s

[root@ora01 ~]# hexdump d1

0000000 8201 0101 0000 0000 0000 8000 2b02 d695

0000010 0000 0000 0000 0000 0000 0000 0000 0000

0000020 524f 4c43 4944 4b53 0000 0000 0000 0000

0000030 0000 0000 0000 0000 0000 0000 0000 0000

0000040 0000 0c10 0000 0302 4144 4154 3130 0000

0000050 0000 0000 0000 0000 0000 0000 0000 0000

0000060 0000 0000 0000 0000 4144 4154 0000 0000

0000070 0000 0000 0000 0000 0000 0000 0000 0000

0000080 0000 0000 0000 0000 4144 4154 3130 0000

0000090 0000 0000 0000 0000 0000 0000 0000 0000

*

00000c0 0000 0000 0000 0000 6e10 01f8 0000 c59c

00000d0 7289 01f8 6800 7f26 0200 1000 0000 0010

00000e0 bc80 0001 77ff 0000 0003 0000 0001 0000

00000f0 0002 0000 000a 0000 0000 0000 0000 0000

0000100 0000 0a10 6e10 01f8 8800 c599 0000 0000

0000110 0000 0000 003c 0000 0001 0000 0001 0000

0000120 0000 0000 0000 0000 140a 2c01 bd86 5a39

0000130 0000 0000 0000 0000 0000 0000 0000 0000

*

0000160 0000 0000 0100 0c20 0000 0000 0000 0000

0000170 0000 0000 0000 0000 0000 0000 0000 0000

*

0001000

No obvious anomalies were found by comparing them to normal ASM disk headers, so try manually establishing ASM disk to device relationships:

[root@ora01 disks]# mknod DATA01 b 202 33

[root@ora01 disks]# mknod DATA02 b 202 49

[root@ora01 disks]# chown grid:asmadmin ./*

[root@ora01 disks]# chmod g+w ./*

[root@ora01 disks]# chmod o-r ./*

Here, we manually establish the corresponding relationship between ASM and equipment through mknod, and then use oracleasm listdisks to view:

[root@ora01 disks]# oracleasm listdisks

DATA01

DATA02

ASM disks have indeed been identified, try mounting the disk group:

SQL> alter diskgroup DATA mount;

Diskgroup altered.

Disk group mounted correctly. Data starts normally.

But when using the oracleasm scanners command:

[root@ora01 disks]# oracleasm scandisks

Reloading disk partitions: done

Cleaning any stale ASM disks...

Cleaning disk "DATA01"

Cleaning disk "DATA02"

Scanning system for ASM disks...

You will find that the two ASM disks created manually are in a stale state and will be cleaned up by the asm driver. This will be studied later. At least it can be used normally now.

Thank you for reading! About "ASM Disk loss how to do" this article is shared here, I hope the above content can have some help for everyone, so that everyone can learn more knowledge, if you think the article is good, you can share it to let more people see it!

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