linux - 如何找出linux进程的打开文件描述？

Question

在运行我的 go 程序时，我在日志中发现了很多错误，例如“打开的文件太多”，我只是想找出哪个进程用完了 fds，然后运行以下命令:

lsof -n |awk '{print $2}'|sort|uniq -c |sort -nr

它返回结果，例如

279605 20341
62748 19861
10310 19712
5434 21318
3484 27344
2842 19781
2400 20372
2346 24153
2123 5214
1540 21123

pid 为 的进程20341 是 蒙哥过程，我对此感到惊讶。所以我尝试了另一种方式:

lsof -p 20341 | wc -l

但让我感到麻烦的是它的结果是: 567 .

之后，我尝试了另一种方式: ll /proc/20341/fd | wc -l结果是 496 。

我现在很困惑，哪一个是对的，他们之间有什么不同？

谢谢。

更新于:2018-05-31 10:35:33

获取mongodb PID
[root@node26 10:34:54 ~]$ps aux | grep mongo
mongodb 20341 2.4 1.9 25419812 1257420 ? Sl May28 107:58 /usr/bin/mongod --quiet -f /etc/mongod.conf run


命令 lsof -p
[root@node26 10:36:12 ~]$lsof -p 20341 | wc -l
570


目录
[root@node26 10:36:33 ~]$ll /proc/20341/fd/ | wc -l
499


命令 lsof + grep
[root@node26 10:37:33 ~]$lsof | grep 20341 | wc -l
282223


前10
mongod 20341 mongodb cwd DIR 9,127 4096 2 /
mongod 20341 mongodb rtd DIR 9,127 4096 2 /
mongod 20341 mongodb txt REG 9,127 12238320 2499177 /usr/bin/mongod
mongod 20341 mongodb mem REG 9,127 67108864 1969114 /var/lib/mongodb/a_dev.0
mongod 20341 mongodb mem REG 9,127 536870912 1968852 /var/lib/mongodb/a_dev.ns
mongod 20341 mongodb mem REG 9,127 67108864 1968447 /var/lib/mongodb/a.0
mongod 20341 mongodb mem REG 9,127 536870912 1968347 /var/lib/mongodb/a.ns
mongod 20341 mongodb mem REG 9,127 67108864 1968453 /var/lib/mongodb/b.0
mongod 20341 mongodb mem REG 9,127 536870912 1968449 /var/lib/mongodb/b.ns
mongod 20341 mongodb mem REG 9,127 67108864 1968590 /var/lib/mongodb/c.0


中间 10
mongod 20341 27018 mongodb 490u IPv4 143223380 0t0 TCP node26:27017->node24:59172 (ESTABLISHED)
mongod 20341 27018 mongodb 491u IPv4 143758325 0t0 TCP node26:27017->node25:43016 (ESTABLISHED)
mongod 20341 27018 mongodb 492u IPv4 143762443 0t0 TCP node26:27017->node24:60602 (ESTABLISHED)
mongod 20341 27018 mongodb 493u IPv4 154865226 0t0 TCP node26:27017->node26:54800 (ESTABLISHED)
mongod 20341 27018 mongodb 494u IPv4 164046515 0t0 TCP node26:27017->node24:42952 (ESTABLISHED)
mongod 20341 27018 mongodb 495u IPv4 164046516 0t0 TCP node26:27017->node24:42960 (ESTABLISHED)
mongod 20341 27018 mongodb 497u IPv4 154865844 0t0 TCP node26:27017->node25:41976 (ESTABLISHED)
mongod 20341 27018 mongodb 500u IPv4 164046517 0t0 TCP node26:27017->node24:42968 (ESTABLISHED)
mongod 20341 27018 mongodb 502u IPv4 164046518 0t0 TCP node26:27017->node26:60306 (ESTABLISHED)
mongod 20341 27018 mongodb 503u IPv4 164046519 0t0 TCP node26:27017->node26:60314 (ESTABLISHED)


尾 10
mongod 20341 32608 mongodb 492u IPv4 143762443 0t0 TCP node26:27017->node24:60602 (ESTABLISHED)
mongod 20341 32608 mongodb 493u IPv4 154865226 0t0 TCP node26:27017->node26:54800 (ESTABLISHED)
mongod 20341 32608 mongodb 494u IPv4 164046515 0t0 TCP node26:27017->node24:42952 (ESTABLISHED)
mongod 20341 32608 mongodb 495u IPv4 164046516 0t0 TCP node26:27017->node24:42960 (ESTABLISHED)
mongod 20341 32608 mongodb 497u IPv4 154865844 0t0 TCP node26:27017->node25:41976 (ESTABLISHED)
mongod 20341 32608 mongodb 500u IPv4 164046517 0t0 TCP node26:27017->node24:42968 (ESTABLISHED)
mongod 20341 32608 mongodb 502u IPv4 164046518 0t0 TCP node26:27017->node26:60306 (ESTABLISHED)
mongod 20341 32608 mongodb 503u IPv4 164046519 0t0 TCP node26:27017->node26:60314 (ESTABLISHED)
mongod 20341 32608 mongodb 505u IPv4 164046523 0t0 TCP node26:27017->node26:60322 (ESTABLISHED)
mongod 20341 32608 mongodb 730u IPv4 117137926 0t0 TCP node26:27017->node25:54730 (ESTABLISHED)


Answer 1

/proc/${pid}/fd包含连接到 shell 的文件描述符，显示为一个数字，后跟一个 u在 lsof :

$ la /proc/$$/fd
total 0
lrwx------ 1 username users 64 May 30 20:08 0 -> /dev/pts/0
lrwx------ 1 username users 64 May 30 20:08 1 -> /dev/pts/0
lrwx------ 1 username users 64 May 30 20:08 2 -> /dev/pts/0
lrwx------ 1 username users 64 May 30 20:08 255 -> /dev/pts/0
$ lsof -p $$
COMMAND  PID     USER   FD   TYPE DEVICE SIZE/OFF    NODE NAME
bash    3720 username  cwd    DIR  254,3    12288 1835009 /home/username
bash    3720 username  rtd    DIR  254,2     4096       2 /
bash    3720 username  txt    REG  254,2   859688 2890163 /usr/bin/bash
bash    3720 username  mem    REG  254,2    46912 2885785 /usr/lib/libnss_files-2.27.so
bash    3720 username  mem    REG  254,2  2942480 2930144 /usr/lib/locale/locale-archive
bash    3720 username  mem    REG  254,2   457800 2890072 /usr/lib/libncursesw.so.6.1
bash    3720 username  mem    REG  254,2  2105608 2885835 /usr/lib/libc-2.27.so
bash    3720 username  mem    REG  254,2    14144 2885777 /usr/lib/libdl-2.27.so
bash    3720 username  mem    REG  254,2   363064 2890132 /usr/lib/libreadline.so.7.0
bash    3720 username  mem    REG  254,2   177680 2885836 /usr/lib/ld-2.27.so
bash    3720 username    0u   CHR  136,0      0t0       3 /dev/pts/0
bash    3720 username    1u   CHR  136,0      0t0       3 /dev/pts/0
bash    3720 username    2u   CHR  136,0      0t0       3 /dev/pts/0
bash    3720 username  255u   CHR  136,0      0t0       3 /dev/pts/0

它们都是“正确的”，但计数来自 lsof是与用完打开文件相关的一个。

要查找相关的打开文件限制，请使用 ulimit -n .