Server Restart
Zend Server includes a multi-faceted restart option that was designed to ensure maximum performance and availability of your server, or cluster.
Smart Restart
This restart type performs a selective restart, restarting only the components that actually need to be restarted. For example, if you have changed a Job Queue component directive, restarting Zend Server from the toolbar will only restart the Job Queue daemon. The other Zend components will not be effected.
A smart restart is performed by clicking the Restart icon in the Zend Server toolbar 
.
), results in a full restart with no loss of session or job related information. Full Restart
This restart type performs a full server restart that includes the Web server, PHP, and Zend Server daemons, directly from the UI. In a cluster, the full restart is performed according to the selected restart strategy.
A full restart can be initiated in two ways:
- In a cluster, from the Servers | Manage
Servers page, by selecting which servers to restart and clicking the
button in the Action bar. - An unwarranted restart, i.e, restarting Zend Server from the toolbar when the Restart icon is dormant .
Daemon Restart
This type of restart only restarts a specific Zend component daemon, and is performed from the Administration | Components page by clicking the restart icon 
for the relevant component.
Restart Strategy
In a clustered environment, to minimize the downtime of your cluster, you can execute an asynchronous restart of your cluster by either selecting to restart a certain percentage of your servers at a time, or by defining a specific amount of servers to be restarted at a time.
For example, in a cluster consisting of ten servers, selecting to restart 50% of your cluster will instruct Zend Server to ensure that a maximum of five servers is restarted at the same time. If you have elected to restart seven servers (by manually selecting them from the Servers list on the Servers | Manage Servers page), Zend Server will only restart five servers as its first task, and as soon as a server vacates a slot, an additional server will begin to restart. This asynchronous process will terminate as soon as all the selected servers have finished to restart.
The restart strategy is configured on the Administration | Settings page. For more information, see Zend Server Settings.
Graceful Restart
Zend Server allows you to determine whether to wait for all processes to be completed before restarting the Web server.