An Overview of Capacity and Performance Information

This topic describes the Delphix Engine performance reservoir and capacity threshold warnings and various ways to obtain information about capacity and resource usage for the Delphix Server.

The Performance Reservoir and Capacity Threshold Warnings

In order to obtain the best performance and continued operations, the Delphix Engine requires a free space of 15% of the total quota for storage space. As storage capacity approaches this threshold, the following system faults occur:

• When 78% of the total storage quota is reached, a Warning fault is triggered. You can resolve this fault by deleting objects in the Delphix Engine, adding storage, or changing policies, as described in the topics Adding and Expanding Storage Devices, Deleting Objects to Increase Capacity, and Changing Snapshot Retention to Increase Capacity. Additionally, refreshing target databases will clear space the engine uses to track changes over time for each DB.
  
  
• When 80% of the total storage quota is reached, performance may decrease as the ZFS file system begins to leverage an algorithm that prioritizes space-savings over performance for storing data.
  
  
• When 85% of the total storage quota is reached, a Critical fault is triggered, and the Delphix Engine will enter Maintenance Mode. When this occurs:
  
  • All pending link, sync, refresh, and provisioning processes will be canceled, and no new operations can be initiated
  • Scheduled replication processes will first check for capacity on the target engine and hold data (replication currently in progress to the engine will not be halted)
  • Policy operations such as SnapSync, snapshot, and refresh are suspended for all engines
  • dSources stop pulling in new changes. LogSync is suspended for all Oracle dSources. Validated sync is disabled for SQL Server dSources.
  • No virtual database (VDB) snapshots can be taken

• When 95% of the total storage quota is reached, a second Critical fault is triggered for SQL Server. All SQL Server VDBs stop in order to maintain data integrity.

To take the system out of Maintenance Mode, increase the storage capacity. You can do this by adding storage devices, deleting objects, or changing policy settings. When you have increased the storage capacity, the system will automatically exit Maintenance Mode.

• When the system falls below 95% of the total storage quota, you can manually start SQL Server VDBs that had stopped
• When the system falls below 90% of the total storage quota, SQL Server VDBs that had stopped will automatically start
• When the system falls below 82% of the total storage quota:
  
  • New link, sync, refresh and provisioning operations are allowed
  • Policy operations such as SnapSync, Snapshot, and Refresh resume for all engines
  • dSources start pulling in new changes from their corresponding data sources. LogSync is resumed for Oracle dSources. Validated sync is enabled for SQL Server dSources.

For more information, see Setting Quotas.

Ways to View Capacity Usage

You can access capacity and performance information for the Delphix Engine through several different means, including the Dashboard view, and the Storage Capacity screen.

The Dashboard View

You can access the Dashboard view in the Delphix Management application by clicking Dashboard in the Manage menu. Note that the Dashboard view provides only summary information about capacity and performance. You must access the Storage Capacity and Dataset Performance screens in the Resources menu to manage storage space and database objects.

The Dashboard view provides more detailed information about the overall performance of the Delphix Engine:

• Storage Capacity - the amount of physical storage available and what is currently used
• TimeFlow Ratio - see above 
  
• VDB Ratio - a measure of the amount of physical space that would be occupied by the database content against the amount of storage occupied by that same database content as VDBs.
• Dataset Performance - the amount of network bandwidth available and the amount that VDBs are currently utilizing, as well as information about specific VDB network usage

The Storage Capacity Screen

You can access the Storage Capacity screen through the Resources menu in the Delphix Management application.
The Storage Capacity screen now has an improved table format. This interface makes it easier to identify which datasets are consuming the most space on your Delphix Engine. It also helps you quickly assess how much storage would become available from deleting selected dSources, VDBs, or snapshots.
The table has been modified for ease of use:

•  Table framing has been lightened to allow the data to stand out.
•  Column separators have been made lighter.
• The filter on the Storage Capacity screen will allow you to filter the datasets.
• The use of gradients has changed.
• Removed the sort-ability of columns. 

The Storage Capacity screen provides a view of storage allocation for dSources, VDBs, and Snapshots by group and objects within the group, as well as a card view that shows Available Space as grey and Used Capacity as blue.

For more information please refer to Using and Understanding The Storage Capacity Screen.

Related Topics

• Using and Understanding The Storage Capacity Screen
• Deleting Objects to Increase Capacity
• Setting Quotas
• Changing Snapshot Retention to Increase Capacity
• Adding and Expanding Storage Devices