[20191204]关于oracle实例是否使用hugepages问题2.txt

[20191204]关于oracle实例是否使用hugepages问题2.txt --//自己最近一段时间一直在关注这个问题,看到一个链接: https://mahmoudhatem.wordpress.com/2019/10/25/hugepage-usage-per-instance/ --//实际上扫描/proc/$pid/smaps获得共享内存段大小.脚本如下: --//我修改一点点.他执行ps -ef | grep $pid | grep -v grep可能有错,因为grep $pid可能查询到无关pmon的进程. --//另外该脚本不能使用在AMM的环境.实际上脚本很简单含有KernelPageSize就是使用hugepages的段. #! /bin/bash total_shmsize=0 total_hugepagesize=0 for pid in `ps -ef | grep ora_pmon_|egrep -v "grep|+ASM"|  awk '{print $2}'` do echo echo "-----------------------------------------------------------" echo # ps -ef | grep $pid | grep -v grep ps v $pid shmsize=`grep -A 1 '/SYSV00000000' /proc/$pid/smaps | grep "^Size:" | awk 'BEGIN{sum=0}{sum+=$2}END{print sum/1024}' |  awk -F"." '{print $1}'` hugepagesize=`grep -B 11 'KernelPageSize:     2048 kB' /proc/$pid/smaps | grep "^Size:" | awk 'BEGIN{sum=0}{sum+=$2}END{print sum/1024}' | awk -F"." '{print $1}'` echo "INSTANCE SGA (SMALL/HUGE page)"  : $shmsize "MB" echo "INSTANCE SGA (HUGE PAGE)" $hugepagesize "MB" echo "Percent Huge page :"  $(( $hugepagesize *100 / $shmsize  )) "%" total_shmsize=$(( $shmsize + $total_shmsize )) total_hugepagesize=$(( $total_hugepagesize + $hugepagesize )) done echo echo "-----------------------------------------------------------" echo echo "SGA TOTAL (SMALL/HUGE page)"  : $total_shmsize "MB" echo "SGA TOTAL (HUGE PAGE)" $total_hugepagesize "MB" echo "Percent Huge page :"  $(( $total_hugepagesize *100 / $total_shmsize  )) "%" --//测试看看: # grep "^vm.nr" /etc/sysctl.conf vm.nr_hugepages = 104 vm.nr_overcommit_hugepages = 1000 SYS@book> startup ORACLE instance started. Total System Global Area  643084288 bytes Fixed Size                  2255872 bytes Variable Size             205521920 bytes Database Buffers          427819008 bytes Redo Buffers                7487488 bytes Database mounted. Database opened. --//alert.log: Starting ORACLE instance (normal) ************************ Large Pages Information ******************* Per process system memlock (soft) limit = 51 GB Total Shared Global Region in Large Pages = 208 MB (33%) Large Pages used by this instance: 104 (208 MB) Large Pages unused system wide = 0 (0 KB) Large Pages configured system wide = 104 (208 MB) Large Page size = 2048 KB RECOMMENDATION:   Total System Global Area size is 618 MB. For optimal performance,   prior to the next instance restart:   1. Increase the number of unused large pages by  at least 205 (page size 2048 KB, total size 410 MB) system wide to   get 100% of the System Global Area allocated with large pages ******************************************************************** --//在混合模式. $ . huge.sh ----------------------------------------------------------- oracle    5565     1  0 17:01 ?        00:00:00 ora_pmon_book INSTANCE SGA (SMALL/HUGE page) : 616 MB INSTANCE SGA (HUGE PAGE) 208 MB Percent Huge page : 33 % ----------------------------------------------------------- ----------------------------------------------------------- SGA TOTAL (SMALL/HUGE page) : 616 MB SGA TOTAL (HUGE PAGE) 208 MB Percent Huge page : 33 % $ ipcs -m ------ Shared Memory Segments -------- key        shmid      owner      perms      bytes      nattch     status 0x00000000 414711809  oracle    640        12582912   25 0x00000000 414744578  oracle    640        159383552  25 0x00000000 414777347  oracle    640        33554432   25 0x00000000 414810117  oracle    640        8388608    25 0x00000000 414842886  oracle    640        4194304    25 0x00000000 414875655  oracle    640        427819008  25 0xe8a8ec10 414908424  oracle    640        2097152    25 --//key=0xe8a8ec10,大小2097152/1024/1024 = 2M.视乎这个多出2M的段比较特殊.