my webserver with 16GB ram shows all RAM as used, but is it really, see the 'top'
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Alex
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Published on 2011-06-28T14:41:43Z
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2011/06/28
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I have some questions about my web server. Its a LAMP web server running centos 5.5 and php5, mysql5. The server gets hundreds (maybe thousand) of concurrent users during peak hours.
I'm trying to optimize a little and understand "top". From what I can see:
all 16GB of my ram have been used up?
does that mean that my server needs more memory?
My swap is only 2GB, should it be increased?
usually during peak hours my server load average first number is about 2.5-3. What could I do to optimize the server so that the load average even during peak doesn't go above 1? In the past I was told a good working server should stay under 1 load, is this still true? Although even during load of 2.5-3, server pages and applications seem to load with pretty good speed.
what should the memory size in php.ini be set to?
top - 14:30:18 up 2 days, 12:41, 5 users, load average: 1.25, 1.74, 2.92
Tasks: 305 total, 2 running, 302 sleeping, 0 stopped, 1 zombie
Cpu(s): 6.3%us, 0.9%sy, 0.0%ni, 92.5%id, 0.2%wa, 0.0%hi, 0.1%si, 0.0%st
Mem: 16427200k total, 16111472k used, 315728k free, 3120316k buffers
Swap: 2104496k total, 268k used, 2104228k free, 6216756k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 29080 apache 15 0 358m 36m 5192 S 20.2 0.2 2:08.40 httpd
29093 apache 18 0 357m 36m 5192 S 18.2 0.2 2:02.52 httpd 29079 apache 15 0 370m 49m 5832 S 10.0 0.3 2:32.14 httpd
1812 apache 15 0 370m 49m 5196 S 7.3 0.3 2:25.30 httpd 5204 apache 15 0 358m 36m 5168 S 5.3 0.2 0:59.28 httpd
29075 apache 15 0 370m 48m 5184 S 3.3 0.3 2:15.93 httpd 9712 apache 15 0 360m 38m 5180 S 3.0 0.2 0:54.81 httpd
29072 apache 16 0 358m 36m 5192 S 2.7 0.2 2:24.43 httpd 6310 apache 17 0 388m 67m 5180 S 2.3 0.4 0:58.85 httpd
8674 apache 15 0 343m 21m 4980 S 2.0 0.1 0:07.91 httpd 29085 apache 15 0 371m 49m 5224 S 2.0 0.3 2:16.86 httpd
29083 apache 15 0 370m 48m 5196 S 1.7 0.3 2:10.64 httpd 5575 apache 15 0 357m 36m 5228 S 1.3 0.2 0:53.78 httpd
29066 apache 15 0 379m 59m 5860 R 1.3 0.4 2:11.93 httpd 29078 apache 15 0 370m 48m 5188 S 1.3 0.3 2:14.52 httpd
29084 apache 15 0 370m 48m 5208 S 1.0 0.3 2:02.49 httpd 29089 apache 15 0 370m 48m 5188 S 1.0 0.3 2:27.61 httpd
29082 apache 15 0 390m 68m 5188 S 0.7 0.4 2:32.48 httpd 29984 apache 15 0 358m 36m 5228 S 0.7 0.2 2:08.32 httpd
3571 root 16 0 13400 1792 848 S 0.3 0.0 2:37.89 top 4419 mysql 15 0 668m 175m 7204 S 0.3 1.1 3:32.25 mysqld
28181 root 15 0 90460 3624 2680 S 0.3 0.0 0:17.60 sshd 29091 apache 15 0 390m 69m 5196 S 0.3 0.4 2:29.99 httpd
32476 root 15 0 12900 1320 848 R 0.3 0.0 0:06.46 top 1 root 15 0 10372 680 572 S 0.0 0.0 0:02.01 init
2 root RT -5 0 0 0 S 0.0 0.0 0:00.51 migration/0 3 root 34 19 0 0 0 S 0.0 0.0 0:00.07 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 0:00.12 migration/1
6 root 34 19 0 0 0 S 0.0 0.0 0:00.03 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 0:00.06 migration/2 9 root 34 19 0 0 0 S 0.0 0.0 0:00.03 ksoftirqd/2
10 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/2 11 root RT -5 0 0 0 S 0.0 0.0 0:00.06 migration/3
12 root 34 19 0 0 0 S 0.0 0.0 0:00.04 ksoftirqd/3 13 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/3
14 root RT -5 0 0 0 S 0.0 0.0 0:01.45 migration/4 15 root 34 19 0 0 0 S 0.0 0.0 0:00.01 ksoftirqd/4
16 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/4 17 root RT -5 0 0 0 S 0.0 0.0 0:00.22 migration/5
18 root 34 19 0 0 0 S 0.0 0.0 0:00.01 ksoftirqd/5 19 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/5
20 root RT -5 0 0 0 S 0.0 0.0 0:00.15 migration/6 21 root 34 19 0 0 0 S 0.0 0.0 0:00.02 ksoftirqd/6
22 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/6 23 root RT -5 0 0 0 S 0.0 0.0 0:00.15 migration/7
24 root 34 19 0 0 0 S 0.0 0.0 0:00.01 ksoftirqd/7 25 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/7
26 root RT -5 0 0 0 S 0.0 0.0 0:00.19 migration/8 27 root 34 19 0 0 0 S 0.0 0.0 0:00.04 ksoftirqd/8
28 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/8 29 root RT -5 0 0 0 S 0.0 0.0 0:00.34 migration/9
30 root 34 19 0 0 0 S 0.0 0.0 0:00.03 ksoftirqd/9 31 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/9
32 root RT -5 0 0 0 S 0.0 0.0 0:00.16 migration/10 33 root 34 19 0 0 0 S 0.0 0.0 0:00.04 ksoftirqd/10
34 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/10 35 root RT -5 0 0 0 S 0.0 0.0 0:00.12 migration/11
36 root 34 19 0 0 0 S 0.0 0.0 0:00.05 ksoftirqd/11 37 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/11
38 root RT -5 0 0 0 S 0.0 0.0 0:00.35 migration/12
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