Monitoring storage capacity for each Storage Node

You must monitor the value of the Total Usable Space (STAS) attribute for each Storage Node to ensure that the node has enough space for new object data.

Before you begin

About this task

STAS is calculated by adding together the available space on all object stores within the Storage Node.

Conceptual drawing for Total Usable Space

Note: If the value of STAS for a Storage Node falls below the value of the Storage Volume Hard Read-Only Watermark, the Storage Node becomes read-only and can no longer store new objects. You should add storage volumes or Storage Nodes before this happens.


  1. Select Nodes > Storage Node > Storage.
    The graphs and tables for the node appear.
  2. Hover your cursor over the Storage Used - Object Data graph.
    A pop-up displays Used (%), Used, and Total capacities. The Total value is the Total Usable Space (STAT) attribute.
    Storage Used - Object Data Graph
  3. Review the values in the tables below the graphs. To view graphs of the values, click the Reports (Charts) icon Report Icon in the Available columns in the Volumes and Object Stores tables.

    Object Stores Tables
  4. Monitor these values over time to estimate the rate at which usable storage space is being consumed.
    Usable space is the actual amount of storage space available to store objects.
  5. To maintain normal system operations, add Storage Nodes, add storage volumes, or archive object data before usable space is consumed.
    The STSS alarm and the Low object storage alert are triggered when insufficient space remains for storing object data on a Storage Node.