How to add a new disk (s) to an existing diskgroup on RAC (best practices ).

 

Before you add the disk (s) to your production diskgroup, you can use the next steps to validate whether the candidate disk (s) is/are in good shape and can be accessed from each node (without harm the existing production diskgroups), as follow:

 

Solution

1) As Oracle OS user, run the next commands on each node (if asmlib API is used ):

$> ID
$>/Etc/init. d/oracleasm scandisks
$>/Etc/init. d/oracleasm listdisks
$>/Etc/init. d/oracleasm querydisk <each disk from previous output>

Note: All the disks must be visible from each node.

2) confirm the disks are visible (I/O) at OS level (as Oracle OS user) from each node:

$> ID
$> Ls-L <disk Name>
$> Dd If = <raw/partition file in question> of =/dev/null COUNT = 100 BS = 8192

Example:

$> Dd If =/dev/raw/raw1 of =/dev/null COUNT = 100 BS = 8192 # raw device
$> Dd If =/dev/oracleasm/disks/proda07 of =/dev/null COUNT = 100 BS = 8192 # asmlib Device

 

3) create a new temporary diskgroup:

SQL> Create diskgroup test external redundancy disk '<your candidate disk> ';

 

4) check if the diskgroup is created and mounted:

SQL> select state, name from V $ asm_diskgroup;

 

5) if so, then manually mount it on the other ASM instance (s ):

SQL> alter diskgroup test Mount;
SQL> select state, name from V $ asm_diskgroup;

 

6 if the previous steps had success and the test diskgroup can be successfully mounted (on each ASM instance), then drop the test diskgroup as follow:

 

SQL> alter diskgroup test dismount; -- (from all the ASM instances, could t from one ).

SQL> drop diskgroup test; -- (from the ASM instance, which the diskgroup is still mounted ).

 

7) then the candidate disk is ready to be added to the desired diskgroup:

SQL> ALTER DISKGROUP <my production diskgroup> ADD DISK '<your candidate disk> ';

 

References

NOTE: 288002.1-OERR: ORA-15075 disk (s) are not visible cluster-wide

 

 

 

 

 

 

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