Monitoring object metadata capacity per Storage Node

StorageGRID Webscale reserves space on volume 0 of each Storage Node for the Cassandra database. This database stores three copies of all object metadata as well as certain configuration data. You can determine what percentage of the space reserved for object metadata is currently being consumed by reviewing the value of the Data Load (Percent) (CDLP) attribute.

Before you begin

About this task

The Metadata Reserved Free Space (CAWM) storage option (Configuration > Storage Options) shows how much space on volume 0 is reserved for storing object metadata. The default value is 2 TB. You can determine what percentage of Metadata Reserved Free Space is currently being consumed by reviewing the value of the Data Load (Percent) (CDLP) attribute.

When this attribute reaches 60% capacity, the CDLP alarm is triggered. This alarm indicates that the amount of storage space reserved for the Cassandra database has reached operating capacity. The Cassandra database requires a certain amount of free storage space to perform essential operations such as compaction and repair. These operations will be impacted if the metadata load continues to grow above 60% capacity.

If you receive a CDLP alarm, expand the StorageGRID Webscale system by adding Storage Nodes. When storage is added, the system automatically rebalances object metadata across all Storage Nodes, and the alarm clears.

Steps

  1. Select Grid.
  2. Select Storage Node > DDS > Datastore.
  3. On the Overview tab, note the current value for the attribute Data Load (Percent) (CDLP).

    Overview page DDS service showing Data Load (Percent) attribute