HP ProLiant DL380G5-WSS 3.7.0 HP StorageWorks HP Scalable NAS File Serving Sof - Page 353

Integrate custom applications, Device monitor or service monitor?

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Integrate custom applications There are many ways to integrate custom applications with HP Scalable NAS: • Use service monitors or device monitors to monitor the application • Use a predefined monitor or your own user-defined monitor • Use Start, Stop, and Recovery scripts Following are some examples of these strategies. Device monitor or service monitor? When deciding whether to monitor your custom application with a service monitor or a device monitor, first determine whether the application provides a service over the network directly to the outside world. If so, you should consider using a service monitor. Because a service monitor is associated with a virtual host, it represents an IP address provided to the outside world to access your services. For example, one common use of HP Scalable NAS is to increase the availability of Web servers. The availability of the HTTP service is best modeled by a service monitor associated with the virtual host to which outside users connect. HP Scalable NAS provides a built-in HTTP service monitor for this use. The other built-in service monitors offer more examples of services which are best modeled by service monitors. If you want to monitor something associated with a physical server, you should consider using a device monitor. Monitoring the health of a local disk drive, for example, is the job of a device monitor. The built-in DISK device monitor is available for this purpose. Similarly, if you have a Web server that communicates with a back-end database, you might want to devise your own user-defined device monitor to determine whether each server in the cluster has a good network connection to the database server. Built-in monitor or user-defined monitor? To decide whether to use a built-in monitor or a user-defined monitor, first determine whether a built-in monitor is available for the service you want to monitor and then consider the degree of content verification that you need. If you are monitoring a custom application for which a built-in monitor is not available but the application provides network services through certain ports, you may consider it sufficient to use built-in TCP monitors on each of those ports. However, if you want to verify that the application is still accepting connections to the port and is also producing reasonable output, you should use a user-defined service monitor. You will need to write a probe HP Scalable NAS File Serving Software administration guide 353

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Integrate custom applications
There are many ways to integrate custom applications with HP Scalable NAS:
Use service monitors or device monitors to monitor the application
Use a predefined monitor or your own user-defined monitor
Use Start, Stop, and Recovery scripts
Following are some examples of these strategies.
Device monitor or service monitor?
When deciding whether to monitor your custom application with a service monitor
or a device monitor, first determine whether the application provides a service over
the network directly to the outside world. If so, you should consider using a service
monitor. Because a service monitor is associated with a virtual host, it represents an
IP address provided to the outside world to access your services.
For example, one common use of HP Scalable NAS is to increase the availability of
Web servers. The availability of the HTTP service is best modeled by a service monitor
associated with the virtual host to which outside users connect. HP Scalable NAS
provides a built-in HTTP service monitor for this use. The other built-in service monitors
offer more examples of services which are best modeled by service monitors.
If you want to monitor something associated with a physical server, you should
consider using a device monitor. Monitoring the health of a local disk drive, for
example, is the job of a device monitor. The built-in DISK device monitor is available
for this purpose. Similarly, if you have a Web server that communicates with a
back-end database, you might want to devise your own user-defined device monitor
to determine whether each server in the cluster has a good network connection to
the database server.
Built-in monitor or user-defined monitor?
To decide whether to use a built-in monitor or a user-defined monitor, first determine
whether a built-in monitor is available for the service you want to monitor and then
consider the degree of content verification that you need. If you are monitoring a
custom application for which a built-in monitor is not available but the application
provides network services through certain ports, you may consider it sufficient to use
built-in TCP monitors on each of those ports. However, if you want to verify that the
application is still accepting connections to the port and is also producing reasonable
output, you should use a user-defined service monitor. You will need to write a probe
HP Scalable NAS File Serving Software administration guide
353