HPE Ezmeral Data Fabric Database and File Store

Describes how HPE Ezmeral Data Fabric Database tables are implemented directly in the Data Fabric file system, which allows HPE Ezmeral Data Fabric Database to leverage the same architecture as the rest of the platform and results in minimal additional management.

  • HPE Ezmeral Data Fabric Database tables are created in logical units called volumes.
  • HPE Ezmeral Data Fabric Database tables are sharded by implementing table regions (also called tablets)
  • Table regions are stored in abstract entities called data containers.
  • Data containers belong to file system volumes.

Tables and Volumes

As volumes are a management entity that logically organize a cluster’s data, they can be used to enforce disk usage limits, set replication levels, define snapshots and mirrors, and establish ownership and accountability.

Volumes do not have a fixed size and they do not occupy disk space until the file system writes data to a container within the volume. A large volume may contain anywhere from 50-100 million containers.

Tables are stored in containers and implemented in volumes, and provide the following capabilities:
  • Multi-Tenancy
  • Snapshots
  • Mirroring and Replication

Table Regions and Containers

Each region of a table, along with its corresponding write-ahead log (WAL) files, b-trees, and other associated structures, is stored in one container. Each container (which can be from 16 to 32 GB in size) can store more than one region (which by default is 4096MB in size). The recommended practice is to use the default size for a region and allow it to be split automatically. Massive regions can affect synchronization of containers and load balancing across a cluster. Smaller regions spread data better across more nodes.

NOTE Since a container always belongs to exactly one volume, that container’s replicas all belong to the same volume as well.
The following are the key advantages to storing table regions in containers:
  • Cluster Scalability
  • High Data Availability

For more information about containers, see Containers and the CLDB.