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Pool of I/O Server Processes |
In applications with hundreds of Drivers, all resources needed to execute I/O Server processes for each Driver may consume operating system's capacity. In these cases, it may be necessary to enable the IOServer Processes Pool group on the Properties tab of a Domain configuration.
When this Pool is enabled, each I/O Server process can execute more than one Driver, then saving operating system resources and thus allowing an application to execute thousands of Drivers.
Only Drivers supporting the creation of new dynamic instances, that is, Drivers compiled with IOKit version 2.0.6 or later, can be used in this Pool. If a Driver without this support is added to this Pool, it is not executed, that is, it fails. For these cases, configure an I/O Driver's DisableIOServerPool property to True, so that it executes outside this Pool, in an exclusive I/O Server process.
On the Properties tab of a Domain configuration, users can control the maximum number of I/O Server processes in this Pool, as well as the maximum number of Drivers that execute on each I/O Server.
Behavior options for a Pool of I/O Server Processes
Drivers per Process |
Maximum Number of Processes |
Pool's Behavior |
|---|---|---|
0 (zero) |
M |
As the Drivers of an application are activated, an I/O Server process is created for each Driver, up to the maximum number M. After that point, every new Driver activated is added to the Pool's I/O Server that contains less Drivers, limited to the maximum number of Drivers per process |
N |
0 (zero) or M |
As the Drivers of an application are activated, Elipse Power adds these Drivers to a Pool's I/O Server process that has not reached the maximum number N of Drivers executing in that Pool. If all processes of that Pool reached their maximum limit, then a new I/O Server is added at run time to that Pool |
NOTES |
•When grouping Drivers in the same I/O Server process, the isolation among these Drivers is lost. Therefore, if one of these Drivers fails, that I/O Server is then closed and all Drivers executing in that I/O Server must be restarted. •Usually, users are not supposed to add more than 100 Drivers in a single I/O Server, because that may exceed the limits of memory of a process. •The number of Drivers per process and the maximum number of processes, that is, the Drivers per process and Maximum number of processes options on the Properties tab of the configuration of a Domain, cannot be configured simultaneously with the value 0 (zero), because this configuration disables the Pool of I/O Server Processes. |