Database resource configuration
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Dear Erman,
Need your expertise We are on oracle version 11.2.0.1.0 supporting tomcat application server We have only one instance running on server.It has 32 GB ram out of which we have assigned 12GB to SGA and 4 GB to PGA as below. 1)From the free output below,We could see the system has 30G free space and the used is 2G.We could not understand why 5G of swap is used here when we have lots of free space.Is this normal?Will this create performance issues? We have 6 physical core and 2 sockets,total 12 cores on this server. 2)Idle shows 90% but some processes are there in runqueue.Is this CPU problem? SQL> sho parameter sga NAME TYPE VALUE ------------------------------------ --------------- ------------------------------ lock_sga boolean FALSE pre_page_sga boolean FALSE sga_max_size big integer 12032M sga_target big integer 12032M SQL> sho parameter pga NAME TYPE VALUE ------------------------------------ --------------- ------------------------------ pga_aggregate_target big integer 4000M SQL> [oracle@PAPLVERTA~]$ free -m total used free shared buffers cached Mem: 32158 22387 9770 0 44 20278 -/+ buffers/cache: 2065 30092 Swap: 63999 5472 58527 [oracle@PAPLVERTA~]$ cat /proc/cpuinfo|grep -i proc|wc -l|grep -v grep 24 NAME TYPE VALUE ------------------------------------ --------------- ----- cpu_count integer 24 parallel_threads_per_cpu integer 2 resource_manager_cpu_allocation integer 24 SQL> [oracle@PAPLVERTA~]$ sar -u 2 5 Linux 2.6.18-194.el5 (SSSTINDCPODB01.SSST.ORG) 06/04/2019 07:33:53 AM CPU %user %nice %system %iowait %steal %idle 07:33:55 AM all 9.83 0.00 2.08 0.04 0.00 88.04 07:33:57 AM all 5.89 0.00 0.19 0.00 0.00 93.92 07:33:59 AM all 7.89 0.00 0.29 0.08 0.00 91.73 07:34:01 AM all 7.39 0.00 1.10 0.00 0.00 91.50 07:34:03 AM all 10.20 0.00 0.75 0.02 0.00 89.03 Average: all 8.24 0.00 0.88 0.03 0.00 90.84 [oracle@PAPLVERTA~]$ SQL> !top top - 07:33:38 up 8 days, 15:26, 1 user, load average: 5.75, 5.99, 5.96 Tasks: 434 total, 4 running, 430 sleeping, 0 stopped, 0 zombie Cpu(s): 5.3%us, 1.2%sy, 0.0%ni, 91.9%id, 1.5%wa, 0.0%hi, 0.1%si, 0.0%st Mem: 32930016k total, 22875996k used, 10054020k free, 57400k buffers Swap: 65535992k total, 5603816k used, 59932176k free, 21100308k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 17641 oracle 16 0 12.0g 1.0g 1.0g R 100.9 3.2 0:33.53 oracleCAPROD (LOCAL=NO) 14411 oracle 20 0 12.0g 1.6g 1.6g R 98.9 5.2 41:25.39 oracleCAPROD (LOCAL=NO) 17194 oracle 24 0 12.2g 4.0g 3.8g R 98.9 12.9 8:38.33 oracleCAPROD (LOCAL=NO) 17698 oracle 15 0 13000 1292 740 R 1.9 0.0 0:00.02 top 1 root 15 0 10348 684 576 S 0.0 0.0 0:12.77 init [5] 2 root RT -5 0 0 0 S 0.0 0.0 0:00.16 [migration/0] 3 root 34 19 0 0 0 S 0.0 0.0 0:00.37 [ksoftirqd/0] 4 root RT -5 0 0 0 S 0.0 0.0 0:00.00 [watchdog/0] 5 root RT -5 0 0 0 S 0.0 0.0 0:00.15 [migration/1] 6 root 34 19 0 0 0 S 0.0 0.0 0:04.33 [ksoftirqd/1] 7 root RT -5 0 0 0 S 0.0 0.0 0:00.00 [watchdog/1] 8 root RT -5 0 0 0 S 0.0 0.0 0:00.02 [migration/2] [oracle@PAPLVERTA~]$ vmstat 2 5 procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------ r b swpd free buff cache si so bi bo in cs us sy id wa st 4 0 5603816 9999456 58344 21102688 0 1 168 426 1 1 5 1 92 1 0 7 0 5603812 9775612 58384 21102732 0 0 1008 168 1273 2908 17 4 79 0 0 7 0 5603812 9475436 58392 21102824 0 0 1000 72 1017 2584 26 3 71 0 0 4 0 5603812 9593280 58448 21102788 0 0 1004 110 1085 2722 18 1 82 0 0 2 0 5603812 9717060 58488 21102812 0 0 1016 146 1168 2803 12 0 87 0 0 [oracle@PAPLVERTA~]$ The recent change is,we have increased SGA from 6gb to 12gb....increased pga size from 1gb tp 4gb. Thank you, satish |
Re: Database resource configuration
Administrator
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1)Linux uses swap in any case.. It is in its nature and that's why Swap usage is not important unless you see lots of swapin and swapout operation.. (you can check using sar utility)
2)You have 12 core and 24 threads then.. If the CPU is idle %90 of the time, then you don't have a big load your server. I will give some additional info to you; Check the load average as well.. So if you have one cpu-core machine. The optimum value for maximum load average is 1. If you have multicore or multicpu machine; our rule of thumb is -> max load average = number of cpu cores. Of course , multicore and multicpu are different in technology, in terms of cache and etc, but this is what we accept roughly.. There are situations where the load average can be high even if the cpu utilization is low. I mean, we can have free cpu cyles in system but we should have to wait for other things.. These situation will lead our load average to increase while our cpu utilization does not change.. |
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Dear erman,
Different meanings for load averages from different sites. Is below definition holds true? the load average represents the average number of processes that have to wait for CPU time during the last 1, 5 or 15 minutes How do you define load average? How do you define the runqueue? Your answers will clarify many confusions about these things Thank you |
Re: Database resource configuration
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Administrator
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In Linux, the load average is calculated as the average number of runnable or running tasks (R state), and the number of tasks in uninterruptible sleep (D state) over the specified interval.
your statement about "Last 1, 5 and 15 minutes" is true. CPU utilization is another thing. High CPU utilization may not necessarily indicate that there is a problem; it could just mean that the system is being well utilized. About runqueue -> Every process enters the runqueue before its processed by the processor. run-queue: Number of active ( running ) and queued processes. For ex: In a 8 core system, a run queue with a length of 100 can be in the form of 8 processes actively being served by CPU and 92 queued and waiting for execution. |
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