Using Maintenance Mode

When you enter a compute module into maintenance mode, it goes offline for service. While a compute module is in maintenance mode A ztC Endurance compute module state that suspends module operation so that it can be serviced. When an active compute module enters maintenance mode, the system performs a Smart Exchange, then activates the standby compute module. Compute modules must be in maintenance mode before they are shut down. Note that placing a ztC Endurance compute module into maintenance mode is unrelated to placing an ESXi host into maintenance mode., operations such as monitoring, recovery, automatic power-on, and so on cannot occur on that compute module.

If you enter the active compute module into maintenance mode, the system automatically performs a Smart Exchange A proprietary process that maintains system availability and protects against data loss. If the ztC Endurance system detects a degradation or failure within the active compute module, Smart Exchange: • Automatically activates the standby compute module and copies over in-process data • Reroutes all I/O and storage connected to the original active compute module to the newly activated compute module Smart Exchange occurs while the system is running and, except for a very brief pause (usually less than one second), is undetectable to the operating system and customer applications.​.

You must manually exit the compute module from maintenance mode to return it to service.

Note the following:

• When the active compute module enters maintenance mode, the standby compute module becomes active after the Smart Exchange completes. During this operation, communications between the active and standby compute modules are disabled, and VMs running on the original active compute module are migrated to the new active compute module. This protects the VMs from any potential disruption caused by the operation.

• When the standby compute module enters maintenance mode, communications between the standby and active compute modules are disabled.

  Notices:  

  1. A compute module must be in maintenance mode before you shut it down. For information about shutting down a compute module, see Shutting Down and Restarting a Compute Module.

  2. The system is not fault tolerant when a compute module is in maintenance mode. For continuous uptime, finalize service as soon as possible so that the compute module can exit maintenance mode and go back online.

To enter a compute module into maintenance mode

1. From the Hardware page, select a compute module.

2. Click Work On.

3. Click Yes on the Confirm window.

   When the compute module is in maintenance mode, its state appears as Maintenance Mode, and its Activity displays as Running. At this point, it is safe to shut down the compute module if necessary.

To exit a compute module from maintenance mode

1. From the Hardware page, select the compute module that is in maintenance mode.

2. Click Finalize, which exits the compute module from maintenance mode.

   When the compute module exits maintenance mode, its state appears as Normal, and its Activity displays as Running.