HANA Disk Usage Test

Since the SAP HANA database resides in volatile main memory, a persistency layer in the SAP HANA database engine ensures the durability of the transactions. In the event of a failure the persistency layer ensures that the database can be restored to the most recent committed state after a restart. Transactions are either completely executed or completely un-done. To ensure durability of data changes completed in the memory of the SAP HANA server nodes, database data is written to disks. The persistency layer stores data in disk volumes, organized in pages. There are two types of volumes: data and log. The data volume contains data pages and undo log information. The log volume only records redo log information. In addition, if tracing is enabled, a trace volume is created, which stores trace files that aid in system troubleshooting.

To enable the SAP HANA database server to provide reliable and uninterrupted data management services, each of these disk volumes should have adequate free space. If a SAP HANA database server were to rapidly run out of disk space, and administrators had no knowledge of this anomaly until it was too late, it could result in the loss of critical data, much to the displeasure of database users. To avoid this, the space usage in each disk volume of the SAP HANA database server host should be closely monitored and administrators forewarned of space contentions. The HANA Disk Usage test makes this possible! This test monitors the space usage in each disk volume of the SAP HANA server, proactively detects a potential space crunch in any volume, and promptly alerts administrators to the same, so that the disk space crisis can be averted.

Target of the test : A SAP HANA Database Server

Agent deploying the test : A remote agent

Outputs of the test : One set of results for every disk volume on the SAP HANA database server host being monitored; each disk volume is represented by <Full_path_to_the_disk>:<VolumeType>, where the VolumeType can be data, log, or trace.

Configurable parameters for the test

Parameter	Description
Test period	How often should the test be executed
Host	The host for which the test is to be configured.
Port	The port number at which the specified Host listens to. By default, this will be 30015.
User	In order to monitor a SAP HANA database server, a special database user account with Monitoring privileges has to be created in every SAP HANA database instance that requires monitoring. The syntax of the script that is used for user creation is discussed in How to Monitor SAP HANA Database Server Using eG Enterprise?. The name of such a user has to be specified here.
Password	Enter the password of the specified User.
Confirm Password	Confirm the password by retyping it here.
IsPassive	If the value chosen for this parameter is Yes, then the SAP HANA database server under consideration is a passive server in a SAP HANA cluster. No alerts will be generated if the server is not running. Measures will be reported as “Not applicable” by the agent if the server is not up.
Exclude Transaction Type	Specify a comma-separated list of transaction types that need to be excluded from the scope of monitoring in this text box. By default, none is specified here.
Detailed Diagnosis	To make diagnosis more efficient and accurate, the eG Enterprise embeds an optional detailed diagnostic capability. With this capability, the eG agents can be configured to run detailed, more elaborate tests as and when specific problems are detected. To enable the detailed diagnosis capability of this test for a particular server, choose the On option. To disable the capability, click on the Off option. The option to selectively enable/disable the detailed diagnosis capability will be available only if the following conditions are fulfilled: The eG manager license should allow the detailed diagnosis capability Both the normal and abnormal frequencies configured for the detailed diagnosis measures should not be 0.

Measurements made by the test

Measurement	Description	Measurement Unit	Interpretation
Total Size	Indicates the total size of this disk volume.	MB
Free Size	Indicates the amount of space that is unused in this disk volume.		A high value is desired for this measure.
Free Percentage	Indicates the percent of space that is currently unused in this disk volume.	Percent	A consistent decrease in the value of this measure is indicative of gradual erosion of space in a disk volume. You may want to free up more space by either adding more disks or by removing unnecessary or obsolete files from the disk. This depends upon the VolumeType. For instance, in case of the data volume, you must not delete files from this volume manually, as it can corrupt the SAP HANA system. On the other hand, if the trace volume runs out of space, you can delete the trace files to make room for more trace data.
Growth	Indicates the percentage growth in space usage in this disk volume since the last measurement period.	Percent	If a consistent growth is noticed in the value of this measure, it is indicative of gradual erosion of space in a disk volume. You may want to free up more space by either adding more disks or by removing unnecessary or obsolete files from the disk. This depends upon the VolumeType. For instance, in case of the data volume, you must not delete files from this volume manually, as it can corrupt the SAP HANA system. On the other hand, if the trace volume runs out of space, you can delete the trace files to make room for more trace data.