Administering Volumes

This section provide information about how to organize and manage data using volumes, a unique feature of MapR clusters.

MapR provides volumes as a way to organize data and manage cluster performance. A volume is a logical unit that allows you to apply policies to a set of files, directories, and sub-volumes. You can use volumes to enforce disk usage limits, set replication levels, establish ownership and accountability, and measure the cost generated by different projects or departments. Create a volume for each user, department, or project.

You can mount volumes under other volumes to build a structure that reflects the needs of your organization. Sub-volumes are created by mounting a volume in a sub-directory of an already mounted volume. This establishes a parent-child relationship between the volumes whereas the parent volume is mounted in top-level directory and the child volume is mounted in the sub-directory. The volume structure defines how data is distributed across the nodes in your cluster. Create multiple small volumes with shallow paths at the top of your cluster's volume hierarchy to spread the load of access requests across the nodes.

A well-structured volume hierarchy is an essential aspect of your cluster's performance. As your cluster grows, keeping your volume hierarchy efficient maximizes data availability. Cluster performance is negatively affected when a volume structure is not in place.

The MapR Control System Volumes page under Data contains the following tabs: