eG Monitoring
 

Measures reported by OraExaCelDSpTest

Within the storage servers, a logical unit number (LUN) defines a logical storage resource from which a single cell disk can be created. A cell disk is an Oracle Exadata System Software abstraction built on the top of a LUN. Soon after a cell disk is created from the LUN, it is managed by Oracle Exadata System Software and is further divided into grid disks, which are directly exposed to the database and Oracle Automatic Storage Management (Oracle ASM) instances. Each grid disk is a potentially non-contiguous partition of the cell disk that is directly exposed to Oracle ASM to be used for the Oracle ASM disk group creations and expansions. This level of virtualization enables multiple Oracle ASM clusters and multiple databases to share the same physical disk. Such sharing also provides optimal use of disk capacity and bandwidth

If a cell disk is in critical state or is running out of space, then the data stored in the cell disk may become unavailable to the users. To avoid such interruption in the availability of data, it is essential to monitor the cell disks at periodic intervals. The OraExaCelDSpTest helps administrators in this regard!

This test auto-discovers the cell disks available in the target Oracle Exadata Storage Server and for each cell disk reports the status and the space utilization. Using this test, administrators can figure out those cell disks to which additional storage space needs to be allocated. Administrators can also isolate the cell disks that are in critical state and initiate remedial measures.

Outputs of the test: One set of results for each cell disk on the target Oracle Exadata Storage Server that is being monitored

Descriptor: Cell disk

The measures made by this test are as follows:

Measurement Description Measurement Unit Interpretation
cellDiskStatus Indicates the current status of this cell disk.  

The table below indicates the values that this measure can report and their corresponding numeric equivalents:

Measure value Numeric Value
Normal 100
Import required 90
Critical 50

Note:

By default, this measure reports the above-mentioned Measure Values while indicating the current status of the cell disk. However, in the graph of this measure, the status of the cell disk will be represented using the corresponding numeric equivalents only.

The detailed diagnosis of this measure lists the date and time on which the cell disk was created, the physical disk associated with the cell disk and the comments.
totalSpace Indicates the total amount of space allocated to this cell disk. TB

 
freeSpace Indicates the amount of space available for use in this cell disk. TB

A high value is desired for this measure.

spaceUtilization Indicates the percentage of space that is utilized by this cell disk. Percent

A value close to 100 indicates that the cell disk is running out of space. Administrators may be required to add additional space to the cell disk.

Compare the value of this measure across cell disks to figure out the cell disk that has utilized maximum amount of space.

errorCount Indicates the total number of errors encountered on this cell disk. Number

Ideally, the value of this measure should be zero.