本文介绍如何通过增加Linux系统参数vm.max_map_count来解决Oracle数据库中遇到的ORA-4030错误。此错误通常发生在虚拟内存区域（VMA）数量达到限制时。通过将vm.max_map_count从默认的65536增加到131072，可以有效地扩大进程可以拥有的VMA数量，从而避免因VMA数量不足导致的问题。
increase vm.max_map_count on linux to avoid ORA-4030
revision 514775 in this collection of tiddlers
# advice from Oracle in SR: double max_map_count from 65536 (=4GB) map entries to result in 8GB
vm.max_map_count=131072
Parameters memory_target and memory_max_target increased also - to cover additional PGA space
About parameter max_map_count:
http://www.redhat.com/magazine/001nov04/features/vm/
max_map_count:
The max_map_count file allows for the restriction of the number of VMAs (Virtual Memory Areas) that a particular process can own. A Virtual Memory Area is a contiguous area of virtual address space. These areas are created during the life of the process when the program attempts to memory map a file, links to a shared memory segment, or allocates heap space. Tuning this value limits the amount of these VMAs that a process can own. Limiting the amount of VMAs a process can own can lead to problematic application behavior because the system will return out of memory errors when a process reaches its VMA limit but can free up lowmem for other kernel uses. If your system is running low on memory in the NORMAL zone, then lowering this value will help free up memory for kernel use.
revision 514775 in this collection of tiddlers
# advice from Oracle in SR: double max_map_count from 65536 (=4GB) map entries to result in 8GB
vm.max_map_count=131072
Parameters memory_target and memory_max_target increased also - to cover additional PGA space
About parameter max_map_count:
http://www.redhat.com/magazine/001nov04/features/vm/
max_map_count:
The max_map_count file allows for the restriction of the number of VMAs (Virtual Memory Areas) that a particular process can own. A Virtual Memory Area is a contiguous area of virtual address space. These areas are created during the life of the process when the program attempts to memory map a file, links to a shared memory segment, or allocates heap space. Tuning this value limits the amount of these VMAs that a process can own. Limiting the amount of VMAs a process can own can lead to problematic application behavior because the system will return out of memory errors when a process reaches its VMA limit but can free up lowmem for other kernel uses. If your system is running low on memory in the NORMAL zone, then lowering this value will help free up memory for kernel use.
http://www.redhat.com/promo/summit/2008/downloads/pdf/Wednesday_1015am_John_Shakshober_and_Larry_Woodman_Decoding_the_Code.pdf /!\ "Deep Dive"
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