Diskgroups Page
ASM simplifies the administration of Oracle data files by defining storage in terms of logical units called disk groups, where each disk group is a set of disk devices. This page categorizes ASM storage data by disk group.
To open the Diskgroups page
- Select the Spotlight on Oracle RAC connection in the Spotlight Browser.
-
Click ASM | Diskgroups.
I/O by Diskgroup
I/O by Diskgroup displays the I/O activity for every ASM disk group associated with the
An ASM disk group is similar to a volume group in third-party storage management products. A disk group comprises two or more disks created to form one volume. Normally disks are allocated in pairs, where one disk is the primary disk and the second disk is used for redundancy or mirrored information.
Disk groups can also be treated as a primary disk, in which case another disk group will be allocated as a failover group: when one group fails, its failover group helps provide continuation of service.
Service Time by Diskgroup
Service Time by Diskgroup shows the actual service time provided by the ASM disk groups assigned to the
Diskgroup Detail Grid
Diskgroup Details displays a list of ASM disk groups configured and assigned to the
| Column | Description |
|---|---|
| Group # | The number assigned to an ASM disk group |
| Name | The name of the disk group. |
| State | The state of the specified ASM disk group relative to the |
| Disks | The number of disks in the disk group. |
| Total MB | The total capacity of the specified ASM disk group (in megabytes). |
| Usable MB |
The unused space on the the disk group (in megabytes). Note: Information not available for Oracle 10.1. |
| Offline Disks |
The number of disks in the disk group that are offline. Note: Information not available for Oracle 10.1. |
| Read IOs | The total number of I/O read requests for the disk group. |
| Write IOs | The total number of I/O write requests for the disk group. |
| IO Reads/s | The rate of I/O read requests for the disk group. |
| IO Writes/s | The rate of I/O write requests for the disk group. |
| Service Time (ms) |
The total service time for all disks in the group (in milliseconds). Note: Service time is the response time of a disk plus any wait time experienced during disk operations. |
| Service Time (avg) | The average service time for all disks in the group (in milliseconds). |
| Block Size | The block size for ASM metadata in the disk group. |
| Redundancy | The redundancy type for the disk group when it belongs to a failure group (EXTERN, NORMAL, or HIGH). |
| Allocation Unit Size | The size of allocation units in the disk group. |
| Oracle says Unbalanced? |
An Oracle SQL query determines if there is unbalanced access to one or more disks in the group. Note: Information not available for Oracle 10.1. |
| Read Errors | The total number of failed I/O read requests for the disk group. |
| Write Errors | The total number of failed I/O write requests for the disk group. |
Tip: For more information on ASM see the Oracle Database Help Center.