Shards Browser

The CrateDB admin UI comes with a shards browser that provides you with a visual overview of all the shards in your cluster.

Note

The shards browser is an enterprise feature.

Table of Contents

Screenshot

Here’s what a simple database might look like:

_images/shards-simple.png

In this example, there are two primary columns:

The blob column lists a single table:

  • my_blobs

The doc column lists two tables:

  • another_table
  • tweets

The table has a single row corresponding to the one node in this cluster. CrateDB automatically names unnamed nodes. In this instance, there is a single node named Monte Civetta.

In this example, the Monte Civetta node is holding the following shards:

  • Three shards for the table named my_blobs
  • Four shards for the table named another_table
  • Four shards for the table named tweets

Shards are colored to indicate their status and there is a color key at the top of the table.

The color of the shards in this example indicates that they are all primary shards and have been successfully started.

Features

Shard ID display:

You can toggle the display of shard IDs by selecting or unselecting the Show Shard IDs checkbox.

Shard status:

Each shard is colored according to its status:

Started Primary:

(bright green)

This is a primary shard that has been successfully started, allocated to a node, and is available for querying.

Started Replica:

(dark green)

This is a replica shard that has been successfully started, allocated to a node, and is available for querying.

Initializing:

(dark yellow)

The shard is being initialized (i.e. being started).

Relocating:

(dark red)

The shard is being relocated to another node.

CrateDB automatically rebalances your cluster for you. While a shard is being moved to another node, it is unavailable for use.

Unassigned:

(gray)

The shard exists on disk, but has not yet been allocated to a node.