How many jvms per server

Learn more. Common and maximum number of virtual machines per server? Ask Question. Asked 10 years, 11 months ago.

Active 9 years ago. Viewed 16k times. Can anybody give practical numbers? Improve this question. Rabarberski Rabarberski 1 1 gold badge 3 3 silver badges 8 8 bronze badges. Please mark your question as community wiki since there's no correct answer. Add a comment. Active Oldest Votes. Improve this answer. TomTom TomTom Austin Velasquez Austin Velasquez 41 1 1 bronze badge. I'd say a reasonable esitmate would be 0 to a million.

Sirex Sirex 5, 2 2 gold badges 30 30 silver badges 54 54 bronze badges. Chopper3 Chopper3 99k 9 9 gold badges silver badges bronze badges. Maximum are VMs, have a look at the links above will give you good insight into it. It also lists all JVM controllers in your environment and allows you to remotely manage them. For example, you can start and stop JVM controllers; add new ones; or reconfigure existing ones.

When a Forms application that is bound to an existing JVM controller requests that the controller start up. It works in a similar way to the Forms configuration file formsweb. The parameters contained in jvmcontrollers. When you start a JVM controller, it takes its settings from the configuration file. You may specify none, some, or all options in this file, both in the default section and in named sections. Section This section describes the common tasks that you can do to edit configuration with the sections of a JVM configuration file and their parameters.

Table describes the tasks you can do with the configuration sections within a JVM configuration file:. Table Tasks for Working with Configuration Sections. Use to create a configuration section based on the parameters of an existing configuration section. Irrevocably deletes a configuration section and its contents when you press Delete in the Confirmation dialog. Creates a new configuration section. You must supply a required name and an optional description for it. Table describes the tasks that you can do to modify the parameters within a named configuration section:.

Add a parameter to a configuration section based on a mandatory name and an optional value and description. Use Apply to save changes or Revert to discard them. Once applied, you cannot revert changes to individual parameters. This section describes creating, editing, duplicating, and deleting named JVM configuration sections. From the Fusion Middleware Control main page, click the link to the Forms Services instance that you want to configure.

You can create new configuration sections in jvmcontrollers. These configurations can be requested in the end-user's query string of the URL that is used to run a form. Enter a name and description for your new configuration section and click Create.

You can edit the description comments for a named configuration from the JVM Configuration page. In the JVM Configuration region, select the row containing the named configuration for which you want to edit the description. The Edit Description dialog box is dismissed, and your changes are saved and displayed. You can make a copy of a named configuration for backup purposes, or create new configuration sections from existing configuration sections. In the Create Like dialog, from the Section to Duplicate menu, select the name of an existing configuration section you want to duplicate.

In the New Section Name field, enter a name for the new configuration section. The name for the new configuration section must be unique. A new section with exactly the same parameters, parameter values and comments of the section you are duplicating is created. When you delete a named configuration section, you delete all the information within it. If you only want to delete specific parameters, see Section From the JVM Configuration region, select the row of the configuration section you want to delete.

Use Fusion Middleware Control to manage parameters within a named configuration. You can add, edit, or delete parameters using Fusion Middleware Control. From the JVM Configuration region, select the row of the configuration section that contains the parameter s you want to edit. Click Apply to save the changes or Revert to discard them. To add a parameter to a configuration section:. In Fusion Middleware Control, from the JVM Configuration region, select the configuration section row for which you want to add a parameter.

In Fusion Middleware Control, from the JVM Configuration region, select the configuration section from which you want to delete a parameter. Table describes the JVM configuration parameters and their default values. When you specify a classpath, it will override the system classpath or any classpath specified in your environment.

If any other directory is set, the log file cannot be viewed through Enterprise Manager. If a JVM controller is down, you can start it. If a JVM controller is already running, you can restart it without first having to manually stop it.

Fusion Middleware Control does this step for you. Select the JVM controller that you want to start. A JVM that is not running is indicated by a red, down arrow. Click the plus symbol next to the JVM controller. The row is expanded to display additional details Figure of the JVM controller. This section describes the JVM pooling parameters that are used in the Forms configuration file formsweb. The parameter names are not case-sensitive. You can use Fusion Middleware Control to administer the Forms configuration file.

For more information on modifying the parameters in formsweb. Note : In order to specify this parameter in formsweb. For more information on otherparams, see Table , "Advanced Configuration Parameters". This parameter can be set globally in the default section, or any application section can choose to override it.

This tells the Forms runtime process which JVM controller to use. It corresponds to the jvmcontroller parameter for the dejvm executable. As shown in Table , formsweb. If a user starts an ordersApp application, and the application executes Java code, the Forms runtime process will route the request to the JVM controller named commonJVM.

Because the [ordersApp] application section does not specify which JVM controller to use, the Forms runtime process uses the global one. If the JVM controller is not started, it will be dynamically started. If a second user starts the same application, it too will attach to commonJVM. When a user starts an hrApp application and it executes Java code, the Forms runtime process sends the request to the JVM controller named hrJVM because the [hrApp] application section overrides the global setting.

When a second user starts the same application, it too will attach to hrJVM. When a second user starts the same application, the application will get their own in-process JVM, thus consuming more memory, as shown in Figure :. Figure Multiple JVMs for multiple applications. This is useful for knowing which Forms runtime processes are connected to which JVM controller for diagnostics or administration;.

You can specify the log file directory in the JVM controller. Create a JVM controller. For more information, see Section Add the Log Directory parameter. If you have duplicated a named configuration section that has Log Directory parameter defined in it, you can edit the existing parameter as given in the Section All requests related to Reports such as running a report on Reports Server, getting the status of a Report, getting Reports output, or cancelling the job submitted to Reports Server are routed to the dejvm for dejvm-enabled runform to make calls to Reports.

The following section Distributing Multi-tier Applications discussed the challenges associated with scaling multi-tier architectures and the ways to solve them in detail. Share-nothing architecture consists of multiple web servers each serving its own copy of data. This architecture works best for static data such as web pages, text, images and videos. The key advantages of this architecture are:. A share-nothing architecture scales horizontally well because it doesn't have to access a shared data source such a database base or file system.

It also offers maximum concurrency because hosts don't compete for shared resources. The fault-tolerance is easily achievable by running multiple hosts serving a copy of the data so that if any of cluster hosts fails, the others simply continue processing requests.

Share-nothing architecture is often implemented as a single-tier system using a web server such as Apache or Nginx. The main disadvantage of the share-nothing architecture is that it doesn't offer data consistency. The share-nothing architecture is rarely used on its own when developing business web applications using Java because data consistency is important. The main source of inconsistency is the delay synchronizing copies of the data in the cluster, which leads to extended periods of time during that the hosts in the cluster respond to requests with different versions of data.

A hybrid application architecture usually consists of a combination of a cluster running business part of the application implemented using a multi-tier architecture and a share-nothing cluster or a content delivery network CDN servicing requests for static data such as images, CSS, videos etc. Because of the disjoint set of disadvantages of the combined architectures, the scalability of the hybrid architecture is limited by the scalability of the business application that drives the consumption of the static data.

To scale the hybrid architecture horizontally by adding more hosts to the cluster, the same scalability challenges characterizing multi-tier applications need to be addressed. While the database plays an important role of reliable transactional data storage, this role also makes it a main bottleneck in the distributed application.

In order to satisfy ACID requirements, the database must process the requests sequentially. As the number of application instances grows, they become increasingly stuck in waiting for responses from the database leaving the benefit of added processing power unrealized. So, the main task when distributing multi-tier Java web applications is making them scalable horizontally by reducing or eliminating the bottleneck caused by the serialized data sources such as database, file systems or remote web services.

This task can be archived by reducing the need to go to the database by caching the frequently requested data. A cache API serves the data from memory in a highly concurrent manner, which allows adding more hosts to the cluster because the application doesn't have to go through the database bottleneck anymore.