# Service Controller

The Service Controller page is the dashboard for the storage service
controller in Storage Management.

The Volume Service Controller (VSC) is zCompute’s storage control plane.
It provides a volume-as-a-service interface to users while abstracting away
the complexity of managing the underlying VPSAs.
VSC is a control-plane component only.
It runs as an independent microservice that sits between zCompute and the
zStorage cloud.
The VSC is the component responsible for managing
and orchestrating storage subsystem components and objects such as VPSAs,
Storage Classes, block storage volumes, volume cloning, snapshots, volume
migrations, backup to Object Storage, and more.

**Key Concepts**:

* **Storage Class**

  An aggregation of one or more uniform VPSAs (same engine type, media
  type, similar drive counts).
  The Storage Class defines high-level capabilities, such as performance
  tier, compression, dedupe, encryption.
* **Volume Type**

  The Volume Type is derived from a Storage Class with specific QoS limits,
  such as maximum read/write IOPS and maximum read/write MB/s.
* **Volume**

  A Volume is provisioned by the end user defined by a selected Volume
  Type. The user specifies capacity, and the VSC handles placement across
  member VPSAs.
* **VSC Hierarchy**
  * VSC high-level architecture:

    ![vsc-high-level-architecture1](media/vsc-high-level-architecture1.png)
    <br/>
  * VSC abstraction: VPSA ↔ Storage Class ↔ Volume Type ↔ Volume:

    ![vsc-high-level-architecture2](media/vsc-high-level-architecture2.png)

**Key Benefits**

* Simplified provisioning: by specifying capacity and QoS, the VSC handles
  VPSA selection and lifecycle.
* Near infinitely scalable EBS via horizontal expansion - adding VPSAs to
  a Storage Class.
* Automatic monitoring of VPSA capacity, performance, and health, with
  volume redistribution to maintain QoS.
* AWS-style volume types and AWS API/CLI storage-pool to volume-type
  compatibility.

The Service Controller page brings command center details, storage summary
values, and VSC events into one central dashboard.

Use this page to review the controller details that the platform
reports, check the current storage counts, and inspect recent storage
controller events.

The page also provides filtering, paging, and related-event access for
the event list.

## Viewing the service controller dashboard

To view the service controller dashboard:

1. Select **Storage Management > Service Controller**.

   The service controller dashboard opens, displaying the
   **Command Center Info** and **Summary** panes in the upper part of the
   screen.

   The lower section of the screen lists summary entries of recent
   **VSC Events**.

### Viewing Command Center Info and Summary

The **Command Center Info** and **Summary** panes appear in the upper part
of the service controller dashboard.

* **Command Center Info** details pane:
  * **IP**

    The command center IP address.
  * **Cloud Name**

    The command center name.
  * **ID**

    The command center’s unique ID.
* **Summary** pane displays the totals of current storage objects and
  protection activity:
  * **Storage Classes**

    The number of storage classes in the cloud.
  * **VPSAs**

    The number of Virtual Private Storage Arrays (VPSAs) associated with
    the cloud.
  * **Volumes**

    The number of volumes in the cloud.
  * **Snapshots**

    The number of snapshots in the cloud, relecting the total sum of
    **Local snapshots** and **Obs snapshots**.
  * **Protection Groups**

    The number of protection groups.
  * **Backup jobs**

    The number of backup jobs.
  * **Restore jobs**

    The number of restore jobs.
  * **Local snapshot**

    The number of local snapshots.
  * **Obs snapshot**

    The number of Remote Object Storage Snapshots snapshots.

### Viewing VSC events

The **VSC Events** pane filters events to display VSC events only.

The VSC Events list has the following columns:

* **Severity**

  The event severity value:
  * **Critical**
  * **Error**
  * **Warning**
  * **Info**
* **Time**

  Date and time that the event occured.
* **Entity Name**

  The entity name linked to the event.
* **Name**

  The event name.
* **Details**

  The event message text.
* **Account**

  The related account, when the event is account-specific.
* **Project**

  The related project, when the event is project-specific.
* **User**

  The username of the user that triggered the event.
* **Related Events**

  Provides access to events related to the event row.

  Selecting **View** redirects to the **Monitoring > Events** screen,
  filtered to events of the row’s **[Event Name]**.
  See also [Monitoring zCompute Events](msp-monitoring-compute-events.md#monitoring-compute-events).

## Recommended best practices

* Review **Command Center Info** first to confirm that the page is
  showing the expected command center record.
* Review **Summary** next. The counts provide a quick status view
  before deeper investigation.
* Set the date range before reading **VSC Events**. This keeps the
  event list focused.
* Use **Filter…** and **More filters** to reduce large result sets.
* Review **Severity**, **Name**, and **Details** together when you
  inspect an event row.
* Open **View** in **Related Events** when one row does not provide
  enough context.

## Troubleshooting

### The page opens, but key values are missing

If the panes load without expected values, confirm the visible page
areas first.

1. Confirm that **Command Center Info** is shown.
2. Confirm that **Summary** is shown.
3. Reload the page and check the panes again.

### The event list is too large to review

Use the visible list controls to reduce the scope.

1. Narrow the date range.
2. Enter text in **Filter…**.
3. Open **More filters** and apply additional limits.
4. Move to the correct page with the paging controls.

### You cannot find the event that you need

The event might be outside the current list view.

1. Expand the date range.
2. Clear the value in **Filter…**.
3. Review more pages by using **1**, **2**, **3**, or the page arrows.

### A single event row is not enough

Some events are easier to review with their linked records.

1. Find the event row.
2. Select **View** in **Related Events**.
3. Review the linked event records.