Database Reference
In-Depth Information
ASM Clients and Relocating
With Flex ASM being enabled, an ASM instance may be connected with various ASM clients from either the local
node or other remote nodes. After logging into the ASM instance, run the following query to see which ASM clients are
connected to this ASM instance:
SQL> select instance_name, db_name, status from v$asm_client;
INSTANCE_N DB_NAME STATUS
---------- ---------- ----------
knewdb_2 knewdb CONNECTED
+ASM2 +ASM CONNECTED
+APX2 +APX CONNECTED
-MGMTDB _mgmtdb CONNECTED
Using this query, we can see how these ASM clients will be failed over to another ASM instance. For example,
we can see how the ASM clients that are connected to +ASM2 are failed over to +ASM1 after +ASM2 fails.
Before ASM2 fails, ASM1 instance has three clients: knewdb_1, +ASM1, and +APX1.
SQL> select instance_name, db_name, status from v$asm_client;
INSTANCE_N DB_NAME STATUS
---------- ---------- ----------
knewdb_1 knewdb CONNECTED
+ASM1 +ASM CONNECTED
+APX1 +APX CONNECTED
And ASM2 is connected with three clients: knewdb_2, +APX2, and -MGMTDB. After ASM2 fails, three clients
from ASM2 instance are relocated to ASM1:
SQL> select instance_name, db_name, status from v$asm_client;
INSTANCE_N DB_NAME STATUS
---------- ---------- ----------
knewdb_1 knewdb CONNECTED
knewdb_2 knewdb CONNECTED
+ASM1 +ASM CONNECTED
+APX1 +APX CONNECTED
+APX2 +APX CONNECTED
-MGMTDB _mgmtdb CONNECTED
New ASM Storage Limits
There is a significant increase in the ASM storage limit pertaining to the number of ASM disk groups. ASM instance
in 12c supports 511 disk groups in contrast to 63 in the previous release.
