Problem creating ASM disk with ASMLib

There are lots of general issues happening or encountering when we are trying to create a new ASM disk. The following case may occur when trying to create an ASM disk with Oracle ASMLib.

I am providing an accurate solution to get rid of this issue. I was working with a client in UK at that time, they were encountering this issue in their Oracle database server. They tried to get rid of this issue but got unsuccessful. They opened a ticket with our Dbametrix. We were providing remote Oracle DBA support to them. My team tried and searched so many things on the web and tested most of the solutions got from blogs and workarounds from Oracle forums and blogs.

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After that, we got a workaround from Oracle support note, and we deployed the same to our client. We got success to create a new ASM disk using the same name and able to map it with the existing Oracle ASM instance. I am describing the same solution here for troubleshooting this kind of mysterious issue of ASM.

[root@ asmserver101 /] # / usr / sbin / oracleasm createdisk ASMDISK201 / dev /mapper /ASMDISK201

Device “/dev /mapper /ASMDISK201” is already labeled for ASM disk “ASMDISK201

[root@ asmserver101/] # multipath -ll

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ASMDISK201 (321260203626233005b20a4sf5ce266) dm-8 DGC, VRAID

size = 4.0G features = ‘1 queue_if_no_path’ hwhandler = ‘1 emc’ wp = rw

| = ‘service-time 0’ prio = 6 status = active

| | – 0: 0: 3: 1 sdi 8:32 active ready running

| `- 3: 0: 3: 1 sde 8:96 active ready running`

– + – policy = ‘service-time 0’ prio = 1 status = enabled

| – 0: 0: 0: 1 sdc 8:128 active ready running

`- 3: 0: 0: 1 sdg 8:64 active ready running

Probably the problem is that the disk is already “marked” as ASM. It might happen because it was already an element of an installation, or for some reason, it was eliminated from ASM and resubmitted. In any of the cases, to solve the problem, simply as the “root” user we execute the following command that steps on the header on the disk, leaving it free of mark:

dd if = /dev / zero of = / dev / mapper / ASMDISK201 bs = 1024 count = 100

Then we attempt to generate the disk again, and we do it without difficulties:

[root@ asmserver101/] # /usr/sbin/oracleasm createdisk ASMDISK201 / dev/mapper/ASMDISK201

Writing disk header: done
Instantiating disk: done

[root@ asmserver101/] # /usr /sbin/oracleasm listdisks

ASMDISK201

[root@ asmserver101/] # / usr / sbin / oracleasm querydisk /dev/mapper/ASMDISK201

Device “/dev/mapper /ASMDISK201” is marked an ASM disk with the label “ASMDISK201”

Using the above trick, you can troubleshoot this mysterious automatic storage management disk issue in the Oracle ASM instance.

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