4.2. Starting and Stopping the glusterd service

Using the glusterd command line, logical storage volumes can be decoupled from physical hardware. Decoupling allows storage volumes to be grown, resized, and shrunk, without application or server downtime.

Regardless of changes made to the underlying hardware, the trusted storage pool is always available while changes to the underlying hardware are made. As storage is added to the trusted storage pool, volumes are rebalanced across the pool to accommodate the added storage capacity.

The glusterd service is started automatically on all servers in the trusted storage pool. The service can also be manually started and stopped as required.

When a Red Hat Gluster Storage server node hosting 256 snapshots of one or more volumes is upgraded to Red Hat Gluster Storage 3.1, the cluster management commands may become unresponsive. This is because, glusterd becomes unresponsive when it tries to start all the brick processes concurrently for all the bricks and corresponding snapshots hosted on the node. This issue can be observed even without snapshots, if there are an equal number of brick processes hosted on a single node.

If the issue was observed in a setup with large number of snapshots taken on one or more volumes, deactivate the snapshots before performing an upgrade. The snapshots can be activated after the upgrade is complete.