由 dawei
我注意到服务器上的内存使用率很高.
细节：
操作系统：CentOS 6.3 – x86_64
Web服务器：使用PHP-FPM的Nginx
服务器正在生成PDF文档,因此流量最小.
最佳：
# top -b -n 1 -a
top - 10:04:51 up 21 days,18:57,1 user,load average: 0.00,0.00,0.00
Tasks: 92 total,1 running,91 sleeping,0 stopped,0 zombie
Cpu(s): 0.3%us,0.2%sy,0.0%ni,99.6%id,0.0%wa,0.0%hi,0.0%si,0.0%st
Mem: 3923092k total,3720380k used,202712k free,133904k buffers
Swap: 4194296k total,12k used,4194284k free,147404k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
15855 www-data 20 0 199m 4952 2128 S 0.0 0.1 0:00.06 php-fpm
15853 www-data 20 0 199m 4940 2028 S 0.0 0.1 0:00.06 php-fpm
15850 www-data 20 0 199m 4928 2020 S 0.0 0.1 0:00.05 php-fpm
15851 www-data 20 0 199m 4888 2020 S 0.0 0.1 0:00.06 php-fpm
15852 www-data 20 0 199m 4852 2020 S 0.0 0.1 0:00.06 php-fpm
15857 www-data 20 0 198m 4716 2020 S 0.0 0.1 0:00.06 php-fpm
17553 root 20 0 97816 3860 2924 S 0.0 0.1 0:00.03 sshd
15849 root 20 0 198m 3460 1072 S 0.0 0.1 0:00.12 php-fpm
13441 nginx 20 0 65608 2968 1604 S 0.0 0.1 0:02.06 nginx
13440 nginx 20 0 65608 2964 1600 S 0.0 0.1 0:01.87 nginx
17561 root 20 0 105m 1944 1488 S 0.0 0.0 0:00.01 bash
1150 xfs 20 0 20980 1784 704 S 0.0 0.0 0:00.13 xfs
15863 root 20 0 179m 1424 1028 S 0.0 0.0 0:00.00 rsyslogd
1 root 20 0 19224 1360 1088 S 0.0 0.0 0:17.96 init
1201 nrpe 20 0 40928 1288 704 S 0.0 0.0 3:57.64 nrpe
13226 root 20 0 114m 1216 612 S 0.0 0.0 0:00.01 crond
6691 root 20 0 64068 1156 488 S 0.0 0.0 0:09.59 sshd
13439 root 20 0 65104 1128 292 S 0.0 0.0 0:00.00 nginx
19026 root 20 0 15040 1116 844 R 0.0 0.0 0:00.00 top
451 root 16 -4 11052 1096 316 S 0.0 0.0 0:00.02 udevd
1174 root 18 -2 11048 1064 288 S 0.0 0.0 0:00.00 udevd
1175 root 18 -2 11048 1064 288 S 0.0 0.0 0:00.00 udevd
1065 root 16 -4 93168 824 560 S 0.0 0.0 0:16.00 auditd
1165 root 20 0 4056 564 480 S 0.0 0.0 0:00.00 mingetty
1167 root 20 0 4056 564 480 S 0.0 0.0 0:00.00 mingetty
1169 root 20 0 4056 564 480 S 0.0 0.0 0:00.00 mingetty
1171 root 20 0 4056 564 480 S 0.0 0.0 0:00.00 mingetty
1163 root 20 0 4056 560 480 S 0.0 0.0 0:00.00 mingetty
1176 root 20 0 4056 560 480 S 0.0 0.0 0:00.00 mingetty
2 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kthreadd
3 root RT 0 0 0 0 S 0.0 0.0 0:11.75 migration/0
4 root 20 0 0 0 0 S 0.0 0.0 44:30.28 ksoftirqd/0
5 root RT 0 0 0 0 S 0.0 0.0 0:00.00 migration/0
6 root RT 0 0 0 0 S 0.0 0.0 0:03.51 watchdog/0
7 root RT 0 0 0 0 S 0.0 0.0 0:11.63 migration/1
8 root RT 0 0 0 0 S 0.0 0.0 0:00.00 migration/1
9 root 20 0 0 0 0 S 0.0 0.0 11:35.50 ksoftirqd/1
10 root RT 0 0 0 0 S 0.0 0.0 0:03.34 watchdog/1
11 root 20 0 0 0 0 S 0.0 0.0 1:36.68 events/0
12 root 20 0 0 0 0 S 0.0 0.0 1:50.57 events/1
13 root 20 0 0 0 0 S 0.0 0.0 0:00.00 cgroup
14 root 20 0 0 0 0 S 0.0 0.0 0:00.00 khelper
15 root 20 0 0 0 0 S 0.0 0.0 0:00.00 netns
16 root 20 0 0 0 0 S 0.0 0.0 0:00.00 async/mgr
17 root 20 0 0 0 0 S 0.0 0.0 0:00.00 pm
18 root 20 0 0 0 0 S 0.0 0.0 0:07.86 sync_supers
19 root 20 0 0 0 0 S 0.0 0.0 0:10.38 bdi-default
20 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kintegrityd/0
21 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kintegrityd/1
22 root 20 0 0 0 0 S 0.0 0.0 0:04.35 kblockd/0
23 root 20 0 0 0 0 S 0.0 0.0 0:04.18 kblockd/1
24 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kacpid
25 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kacpi_notify
26 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kacpi_hotplug
27 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ata/0
28 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ata/1
29 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ata_aux
30 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ksuspend_usbd
31 root 20 0 0 0 0 S 0.0 0.0 0:00.00 khubd
32 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kseriod
33 root 20 0 0 0 0 S 0.0 0.0 0:00.00 md/0
34 root 20 0 0 0 0 S 0.0 0.0 0:00.00 md/1
35 root 20 0 0 0 0 S 0.0 0.0 0:00.00 md_misc/0
36 root 20 0 0 0 0 S 0.0 0.0 0:00.00 md_misc/1
37 root 20 0 0 0 0 S 0.0 0.0 0:00.48 khungtaskd
38 root 20 0 0 0 0 S 0.0 0.0 1:07.52 kswapd0
39 root 25 5 0 0 0 S 0.0 0.0 0:00.00 ksmd
40 root 39 19 0 0 0 S 0.0 0.0 0:22.00 khugepaged
41 root 20 0 0 0 0 S 0.0 0.0 0:00.00 aio/0
42 root 20 0 0 0 0 S 0.0 0.0 0:00.00 aio/1
43 root 20 0 0 0 0 S 0.0 0.0 0:00.00 crypto/0
44 root 20 0 0 0 0 S 0.0 0.0 0:00.00 crypto/1
49 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kthrotld/0
50 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kthrotld/1
52 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kpsmoused
53 root 20 0 0 0 0 S 0.0 0.0 0:00.00 usbhid_resumer
83 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kstriped
233 root 20 0 0 0 0 S 0.0 0.0 0:00.00 scsi_eh_0
234 root 20 0 0 0 0 S 0.0 0.0 0:00.00 scsi_eh_1
321 root 20 0 0 0 0 S 0.0 0.0 0:00.00 virtio-blk
359 root 20 0 0 0 0 S 0.0 0.0 0:03.24 kdmflush
360 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kdmflush
380 root 20 0 0 0 0 S 0.0 0.0 0:20.64 jbd2/dm-0-8
381 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ext4-dio-unwrit
382 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ext4-dio-unwrit
694 root 20 0 0 0 0 S 0.0 0.0 0:00.00 vballoon
697 root 20 0 0 0 0 S 0.0 0.0 0:00.00 virtio-net
818 root 20 0 0 0 0 S 0.0 0.0 0:00.00 jbd2/vda1-8
819 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ext4-dio-unwrit
820 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ext4-dio-unwrit
851 root 20 0 0 0 0 S 0.0 0.0 0:06.96 kauditd
1013 root 20 0 0 0 0 S 0.0 0.0 0:15.45 flush-253:0
PS：