Oracle警告日志WARNING : Parameter _linux_prepage_large_pages Is Explicitly Disabled
在集群上创建了6个实例后，启动实例警告日志有如下警告信息：
Starting ORACLE instance (normal) ************************ Large Pages Information ******************* Per process system memlock (soft) limit = UNLIMITED Large page usage restricted to processor group "system.slice/ohasd.service" Total Shared Global Region in Large Pages = 13 GB (100%) WARNING: The parameter _linux_prepage_large_pages is explicitly disabled. Oracle strongly recommends setting the _linux_prepage_large_pages parameter since the instance is running in a Processor Group. If there is insufficient large page memory, instance may encounter SIGBUS error and may terminate abnormally. Large Pages used by this instance: 6561 (13 GB) Large Pages unused in Processor Group system.slice/ohasd.service = 16439 (32 GB) Large Pages configured in Processor Group system.slice/ohasd.service = 23000 (45 GB) Large Page size = 2048 KB ********************************************************************
之前只有1个实例的时候并不会提示这类信息，包括以前经验配置那么多数据库也是没见过。
猜测这是因为集群注册多个实例以上才会发生，第二就是不是集群可能多个实例也不会提示。找个机会验证下。
当我6个实例全部打开后，查看大页使用情况发现并没有的大页内存被使用上。
[oracle@dev-testdb ~]$ grep -i hugepage /proc/meminfo AnonHugePages: 0 kB ShmemHugePages: 0 kB FileHugePages: 0 kB HugePages_Total: 23000 HugePages_Free: 18392 HugePages_Rsvd: 18358 HugePages_Surp: 0 Hugepagesize: 2048 kB
当根据建议设置"_linux_prepage_large_pages"=TRUE后，重启全部实例，则为：
grep -i hugepage /proc/meminfo AnonHugePages: 0 kB ShmemHugePages: 0 kB FileHugePages: 0 kB HugePages_Total: 23000 HugePages_Free: 34 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB
参考文档
WARNING : Parameter _linux_prepage_large_pages Is Explicitly Disabled (文档 ID 2414778.1)