.. _Monitoring Storage Cluster Node Performance:

Monitoring Storage Cluster Node Performance
-------------------------------------------

To monitor the performance of a storage cluster node, open the **NODES** screen and click a node. On the node overview screen, you will see performance statistics described below.

The overall statistics include:

- the number of CPUs and the amount of RAM,

- CPU usage, in percent over time,

- RAM usage, in percent over time.

.. image:: /images/stor_image29.png
   :align: center
   :class: align-center

The **DISKS** section shows:

- the number of HDD and SSD drives and their statuses,

- node I/O activity over time on the read and write charts.

.. image:: /images/stor_image30.png
   :align: center
   :class: align-center
 
The **NETWORK** section shows:

- the list of network interfaces and their statuses,

- the amount of transmitted (TX) and received (RX) traffic over time.

.. image:: /images/stor_image31.png
   :align: center
   :class: align-center

The following sections provide more information on disk and network usage.

.. _Monitoring Storage Cluster Node Disks:

Monitoring Storage Cluster Node Disks
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

To monitor the usage and status of node disks, click the **DISKS** link on the node overview screen. You will see a list of all disks on the node and their status icons.

A disk status icon shows the combined status of S.M.A.R.T. and the service corresponding to the disk role. It can be one of the following:

- **OK**. The disk and service are healthy.

- **Failed**. The service has failed or S.M.A.R.T. reported an error.

- **Releasing**. The service is being released. When the process finishes, the disk status will change to **Ok**.

On this screen, you can:

- monitor the details and performance of each disk,

- manage disk roles,

- have the disk blink its activity LED. Works only for LSI and PERC controllers.

To monitor performance of a particular disk, select it and click **Performance**. The **Drive performance** panel will display the I/O activity of the disk.

To view information about the disk, including its S.M.A.R.T. status, click **Details**.

To have the disk blink its activity LED, select the disk, and click **Blink**. To have the disk stop blinking, click **Unblink**.

.. _Monitoring the S.M.A.R.T. Status of Node Disks:

Monitoring the S.M.A.R.T. Status of Node Disks
**********************************************

The S.M.A.R.T. status of all disks is monitored by a tool installed along with |product_name|. Run every 10 minutes, the tool polls all disks attached to nodes, including journaling SSDs and system disks, and reports the results to the management node.

.. note::  For the tool to work, make sure the S.M.A.R.T. functionality is enabled in node's BIOS.

If a S.M.A.R.T. warning message is shown in the node status, one of that node's disks is in pre-failure condition and should be replaced. If you continue using the disk, keep in mind that it may fail or cause performance issues.

Pre-failure condition means that at least one of these S.M.A.R.T. counters is not zero:

- Reallocated Sector Count

- Reallocated Event Count

- Current Pending Sector Count

- Offline Uncorrectable