[20191119]探究ipcs命令输出2.txt

来源：这里教程网时间：2026-03-03 14:33:39 作者：

[20191119]探究ipcs命令输出2.txt --//继续上午的测试:http://blog.itpub.net/267265/viewspace-2664758/=>[20191119]探究ipcs命令输出.txt --//先补充ipcs 剩余2个参数 -l -u --//-l limits --//-u summary $ ipcs -l ------ Shared Memory Limits -------- max number of segments = 4096 max seg size (kbytes) = 67108864 max total shared memory (kbytes) = 17179869184 min seg size (bytes) = 1 ------ Semaphore Limits -------- max number of arrays = 128 max semaphores per array = 2600 max semaphores system wide = 332800 max ops per semop call = 2600 semaphore max value = 32767 ------ Messages: Limits -------- max queues system wide = 32768 max size of message (bytes) = 65536 default max size of queue (bytes) = 65536 $ ipcs -u ------ Shared Memory Status -------- segments allocated 5 pages allocated 158305 pages resident 129633 pages swapped 0 Swap performance: 0 attempts 0 successes ------ Semaphore Status -------- used arrays = 1 allocated semaphores = 204 ------ Messages: Status -------- allocated queues = 0 used headers = 0 used space = 0 bytes --//剩下kernel.sem = SEMMSL SEMMNS SEMOPM SEMMNI kernel.sem = SEMMSL SEMMNS SEMOPM SEMMNI where semmsl: The number of semaphores per set 每组信号量 semmns: The total number of semaphores available 可用信号量的总数 semopm: The number of operations which can be made per semaphore call 每个信号量呼叫可以执行的操作数。 semmni: The maximum number of shared memory segments available in the system 系统中可用的最大共享内存段数 --//(我觉得这里是指信号量)。 1.环境: # grep "^kernel.s[he]" /etc/sysctl.conf kernel.shmmax = 68719476736 kernel.shmall = 4294967296 kernel.shmmni = 4096 kernel.sem = 2600 332800 2600 128 SCOTT@book> show sga Total System Global Area 643084288 bytes Fixed Size 2255872 bytes Variable Size 205521920 bytes Database Buffers 427819008 bytes Redo Buffers 7487488 bytes SCOTT@book> show parameter processes NAME TYPE VALUE --------- ------- ----- processes integer 200 --//重新定义环境变量 export ORACLE_SID=book --//顺便说一下我的定义:kernel.sem = 2600 332800 2600 128 --//实际上我开始学oracle什么都不懂,上新闻组问了这个问题,对方给我的解答.第一个参数与processes有关在此基础上+10就可以. --//第2个参数使用第1个参数*第4个参数 = 2600*128 = 332800.第3个参数他给我的建议等于第1个参数. --//我当时什么都不懂,既然对方这么建议,按照对方建议先尝试看看.以后也没有在意这个参数,剩下的步骤copy and paste. --//如果大家看我在单位安装的服务器,基本上这个参数都是这样设置.经典copy and paste操作. 2.测试1: $ ipcs ------ Shared Memory Segments -------- key shmid owner perms bytes nattch status 0x00000000 407011329 oracle 640 12582912 25 0x00000000 407044098 oracle 640 633339904 25 0xe8a8ec10 407076867 oracle 640 2097152 25 ------ Semaphore Arrays -------- key semid owner perms nsems 0x6aa88594 328302592 oracle 640 204 ------ Message Queues -------- key msqid owner perms used-bytes messages $ ps -ef | egrep "[o]raclebook|ora_.*_boo[k]"|wc 25 201 1597 --//注意看Semaphore Arrays的nsems=204,也就是sem的数量.你可以测试如果processes增加,该数值也会增加相同的数量. --//当然我当前设置kernel.sem的semmsl=2600,远远超出processes的数值,不会建立多个信号组. $ ipcs -s -i 328302592 | awk '/semnum/,/^203/' | awk '$5>0 {print $5}' | sort | uniq -c 5 56258 1 56261 1 56263 1 56269 1 56273 1 56277 1 56279 1 56281 1 56283 1 56285 1 56287 1 56289 1 56291 1 56293 1 56295 1 56306 1 56307 1 56309 1 56311 1 56313 1 56321 1 56323 1 56325 1 56327 1 56329 1 pid $ ipcs -s -i 328302592 | awk '/semnum/,/^203/' | awk '$5>0 ' semnum value ncount zcount pid 0 0 0 0 56258 1 2559 0 0 56258 2 19574 0 0 56258 3 1 0 0 56258 6 0 0 0 56261 7 0 1 0 56263 9 0 1 0 56269 11 0 1 0 56273 13 0 1 0 56277 14 0 1 0 56279 15 0 1 0 56281 16 0 1 0 56283 17 0 1 0 56285 18 0 1 0 56287 19 0 1 0 56289 20 0 1 0 56291 21 0 1 0 56293 22 0 1 0 56295 25 0 0 0 56307 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 26 0 1 0 56306 27 0 1 0 56309 28 0 1 0 56311 29 0 1 0 56313 30 0 1 0 56329 31 0 0 0 56327 32 0 0 0 56321 33 0 0 0 56323 34 0 0 0 56325 203 0 0 0 56258 --//semnum应该表示序号.pid对应进程号.其它value,ncount,zcount 表示什么,不懂. --//https://blog.csdn.net/macky0668/article/details/6839559 --//ncount列出等待信号量增加的进程的个数. --//zcount列出正在等待信号量变成零的进程的个数 $ ps -fp 56307 UID PID PPID C STIME TTY TIME CMD oracle 56307 56254 0 15:35 ? 00:00:00 oraclebook (DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq))) --//疑问什么情况下ncount=1,pid=56307.视乎是使用后信号量后才会增加. $ ps -fp 56258 UID PID PPID C STIME TTY TIME CMD $ ipcs -m -p ------ Shared Memory Creator/Last-op -------- shmid owner cpid lpid 407011329 oracle 56258 56458 407044098 oracle 56258 56458 407076867 oracle 56258 56458 --//Shared Memory Creator 的pid=56258,已经不存在.但是你可以发现Semaphore Array semid=328302592中占5行. --//视乎前面的4行永远不会覆盖.也就是kernel.sem的semmsl大于processes+4才会仅仅使用Semaphore Arrays. # grep "^kernel.s[he]" /etc/sysctl.conf kernel.shmmax = 68719476736 kernel.shmall = 4294967296 kernel.shmmni = 4096 kernel.sem = 100 332800 100 128 # sysctl -p 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. $ ipcs -s ------ Semaphore Arrays -------- key semid owner perms nsems 0x6aa88594 328433664 oracle 640 51 0x6aa88595 328466433 oracle 640 51 0x6aa88596 328499202 oracle 640 51 0x6aa88597 328531971 oracle 640 51 0x6aa88598 328564740 oracle 640 51 $ ipcs -u -m ------ Shared Memory Status -------- segments allocated 5 pages allocated 158305 pages resident 111201 pages swapped 0 Swap performance: 0 attempts 0 successes --//建立了5个Semaphore Array,每个大小nsems=51. --//为什么不建立3个Semaphore Array,nsems=100或者70? $ ipcs -m -p ------ Shared Memory Creator/Last-op -------- shmid owner cpid lpid 407142401 oracle 56667 56733 407175170 oracle 56667 56733 407207939 oracle 56667 56733 $ ipcs -s | awk '/0x/ {print $2}' | xargs -I {} ipcs -s -i {} | grep 56667 0 1 0 0 56667 1 2559 0 0 56667 2 19574 0 0 56667 3 1 0 0 56667 0 1 0 0 56667 1 2559 0 0 56667 2 19574 0 0 56667 3 1 0 0 56667 0 1 0 0 56667 1 2559 0 0 56667 2 19574 0 0 56667 3 1 0 0 56667 0 1 0 0 56667 1 2559 0 0 56667 2 19574 0 0 56667 3 1 0 0 56667 0 0 0 0 56667 1 2559 0 0 56667 2 19574 0 0 56667 3 1 0 0 56667 15 0 0 0 56667 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ --//不知道它的具体算法.视乎每个array前面4个都是建立pid. --//贴一个processes=1000的情况,asm实例的processes=1320的情况 # grep "^kernel.s[eh]" /etc/sysctl.conf kernel.shmmax = 61847529062 kernel.shmall = 15099494 kernel.shmmni = 4096 kernel.sem = 250 32000 100 128 $ ipcs -s ------ Semaphore Arrays -------- key semid owner perms nsems 0x869d3e0c 163842 grid 640 165 0x869d3e0d 196611 grid 640 165 0x869d3e0e 229380 grid 640 165 0x869d3e0f 262149 grid 640 165 0x869d3e10 294918 grid 640 165 0x869d3e11 327687 grid 640 165 0x869d3e12 360456 grid 640 165 0x869d3e13 393225 grid 640 165 0x869d3e14 425994 grid 640 165 0x42dc1a48 2392075 oracle 640 250 0x42dc1a49 2424844 oracle 640 250 0x42dc1a4a 2457613 oracle 640 250 0x42dc1a4b 2490382 oracle 640 250 0x42dc1a4c 2523151 oracle 640 250 0x42dc1a4d 2555920 oracle 640 250 0x42dc1a4e 2588689 oracle 640 250 0x42dc1a4f 2621458 oracle 640 250 0x42dc1a50 2654227 oracle 640 250 $ ipcs -s -u ------ Semaphore Status -------- used arrays = 20 allocated semaphores = 3737 --//也不知道多个Semaphore Array对性能有什么影响,视乎从来没有人提到这样对性能存在问题.我看了exadata的设置: exadata# grep "^kernel.s[he]" /etc/sysctl.conf kernel.shmmax = 229982982348 kernel.shmall = 56148189 kernel.shmmni = 4096 kernel.sem = 1024 60000 1024 256 --//我个人感觉也许应该根据processes的数量适当调整,不要建立太多的Semaphore Array. 3.测试2: --//最后测试kernel.sem的第4个参数SEMMNI. kernel.sem = SEMMSL SEMMNS SEMOPM SEMMNI semmni: The maximum number of shared memory segments available in the system 系统中可用的最大共享内存段数 --//(我觉得这里是指信号量)。 # grep "^kernel.s[he]" /etc/sysctl.conf kernel.shmmax = 68719476736 kernel.shmall = 4294967296 kernel.shmmni = 4096 kernel.sem = 100 332800 100 4 # sysctl -p SYS@book> startup ORA-27154: post/wait create failed ORA-27300: OS system dependent operation:semget failed with status: 28 ORA-27301: OS failure message: No space left on device ORA-27302: failure occurred at: sskgpcreates --//无法启动数据库. # grep "^kernel.s[he]" /etc/sysctl.conf kernel.shmmax = 68719476736 kernel.shmall = 4294967296 kernel.shmmni = 4096 kernel.sem = 100 332800 100 5 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. $ ipcs -a ------ Shared Memory Segments -------- key shmid owner perms bytes nattch status 0x00000000 407404545 oracle 640 12582912 25 0x00000000 407437314 oracle 640 633339904 25 0xe8a8ec10 407470083 oracle 640 2097152 25 ------ Semaphore Arrays -------- key semid owner perms nsems 0x6aa88594 328925184 oracle 640 51 0x6aa88595 328957953 oracle 640 51 0x6aa88596 328990722 oracle 640 51 0x6aa88597 329023491 oracle 640 51 0x6aa88598 329056260 oracle 640 51 ------ Message Queues -------- key msqid owner perms used-bytes messages 4.还原测试环境略. # grep "^kernel.s[he]" /etc/sysctl.conf kernel.shmmax = 68719476736 kernel.shmall = 4294967296 kernel.shmmni = 4096 kernel.sem = 2600 332800 2600 128 5.总结: --//操作系统的许多东西自己还是存在许多不理解的情况,许多东西纯粹自己在乱猜.毕竟不是自己的专业,需要慢慢积累学习提高.