Best practices for disk space management
This content applies only to On-premises and Client-managed cloud environments
You can maintain the high performance of decision services in your application by following best practices for allocating disk space to the Decision Data Store (DDS) nodes.
- For DDS nodes, perform the following actions:
- Assign a maximum of 1 TB of DDS data per Cassandra node, with a maximum of 100 GB per node for a single table.
- Facilitate compaction by ensuring at least 2 TB of disk space.
Use an HDD with a maximum capacity of 1 TB, or an SSD with a maximum capacity of between 2 and 5 TB.
- Ensure that all DDS nodes have the same disk capacity.
- Store the commit log and caches on separate disks by configuring the following properties: dnode/yaml/commitlog_directory and dnode/yaml/saved_caches_directory.
- For application data, perform the following actions:
- Avoid distributing data unequally across nodes by limiting the size of a
single data record to less than 100 MB.
For DDS data sets, when the size of the data record exceeds the threshold limit, Pega Platform triggers the PEGA0079 alert.
- Avoid splitting records across nodes by writing short rows.
For example, do not write to a table as a ping test by using the same partition key repeatedly.
- Avoid distributing data unequally across nodes by limiting the size of a
single data record to less than 100 MB.
- Monitor the available disk space on a regular basis.For more information, see Verifying the available disk space.
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