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(→Stack Size)
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(→JVM (IBM) Options)
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| ''The following options deal with the heap size of the server java process as well as garbage collection performance. It is recommended that users perform their own analysis, using the -verbose:gc & -Xverbosegclog<filename> flags as well as -Xms64m -Xmx3g (32 bit) or -Xmx6g (64 bit), to determine what heap sizes and ratios work best for them.'' | ''The following options deal with the heap size of the server java process as well as garbage collection performance. It is recommended that users perform their own analysis, using the -verbose:gc & -Xverbosegclog<filename> flags as well as -Xms64m -Xmx3g (32 bit) or -Xmx6g (64 bit), to determine what heap sizes and ratios work best for them.'' | ||
| - | * -Xms### | ''Sets the minimum heap size to "###". Generally for moderate systems this should be 768m. DO NOT FORGET SIZE DESCRIPTOR (k, m, g).'' | ||
| - | * -Xmx### | ''Sets the maximum heap size to "###". Generally for moderate systems this should be 2g (32 bit) or 4g (64 bit). DO NOT FORGET SIZE DESCRIPTOR (k, m, g).'' | + | == Heap == |
| - | * -Xmaxf## | ''Sets the maximum percentage of free heap space before the size is reduced but not lower than the Xms setting. This number should be between 0.35 and 1.0 and approximately 30 points higher than the minimum heap ratio. A good starting point for this value is 0.55.'' | + | * -Xms### |
| - | * -Xminf## | ''Sets the minimum percentage of free heap space before the size is increased but not greater than the Xmx setting. This number should be between 0.05 and 0.75 and approximately 30 points lower than the maximum heap ratio. A good starting point for this value is 0.25.'' | + | ** ''Sets the minimum heap size to "###". Generally for moderate systems this should be 768m. DO NOT FORGET SIZE DESCRIPTOR (k, m, g).'' |
| + | * -Xmx### | ||
| + | ** ''Sets the maximum heap size to "###". Generally for moderate systems this should be 2g (32 bit) or 4g (64 bit). DO NOT FORGET SIZE DESCRIPTOR (k, m, g).'' | ||
| + | * -Xmaxf## | ||
| + | ** ''Sets the maximum percentage of free heap space before the size is reduced but not lower than the Xms setting. This number should be between 0.35 and 1.0 and approximately 30 points higher than the minimum heap ratio. A good starting point for this value is 0.55.'' | ||
| + | * -Xminf## | ||
| + | ** ''Sets the minimum percentage of free heap space before the size is increased but not greater than the Xmx setting. This number should be between 0.05 and 0.75 and approximately 30 points lower than the maximum heap ratio. A good starting point for this value is 0.25.'' | ||
| + | == Garbage Collection == | ||
| * -Xgcthreads# | ''Sets the number of threads the garbage collector can use in parallel. Generally this number should roughly correlate to the number of cores available in your system but not more than double.'' | * -Xgcthreads# | ''Sets the number of threads the garbage collector can use in parallel. Generally this number should roughly correlate to the number of cores available in your system but not more than double.'' | ||
| * -Xdisableexplicitgc | ''Disables the server from initiating garbage collection directly. This will ensure that the settings described above are honored and the system is not overwhelmed by unexpected garbage collection runs.'' | * -Xdisableexplicitgc | ''Disables the server from initiating garbage collection directly. This will ensure that the settings described above are honored and the system is not overwhelmed by unexpected garbage collection runs.'' | ||
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| + | == Thread Stack Size == | ||
| ''The following options deal with the thread size used for server processes. Users are again encouraged to investigate memory usage patterns on their systems to determine useful tweaks to these settings.'' | ''The following options deal with the thread size used for server processes. Users are again encouraged to investigate memory usage patterns on their systems to determine useful tweaks to these settings.'' | ||
| * -Xiss### | ''Sets the initial thread stack size to "###". For most systems this should be set the same as the maximum stack size at 128k (32 bit) or 256k (64 bit). DO NOT FORGET SIZE DESCRIPTOR (k, m, g).'' | * -Xiss### | ''Sets the initial thread stack size to "###". For most systems this should be set the same as the maximum stack size at 128k (32 bit) or 256k (64 bit). DO NOT FORGET SIZE DESCRIPTOR (k, m, g).'' | ||
