生產(chǎn)環(huán)境某個服務(wù)報Too many open files問題
1、首先確認(rèn)允許打開的最大文件數(shù)是多少
[root@101 ~]# ulimit -a
core file size (blocks, -c) unlimited
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 15215
max locked memory (kbytes, -l) 64
max memory size (kbytes, -m) unlimited
open files (-n) 65535
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 0
stack size (kbytes, -s) unlimited
cpu time (seconds, -t) unlimited
max user processes (-u) 65535
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited
看open files參數(shù)，結(jié)果是65535，挺大的了
2、查看系統(tǒng)現(xiàn)在打開的文件數(shù)
[root@101 ~]# lsof |wc -l
66801
3、查看java進(jìn)程打開的文件數(shù)
[root@101 ~]# lsof -p 12025|wc -l
65613
12025是進(jìn)程id，65613超過了系統(tǒng)設(shè)置的65535了
4、查看進(jìn)程打開了哪些文件
[root@101 ~]# lsof -p 12025
java 12025 tomcat 92r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 93r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 94r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 95r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 96r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 97r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 98r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 99r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 100r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 101r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 102r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 103r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 104r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 105r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 106r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 107r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 108r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 109r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 110r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 111r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 112r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 113r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 114r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 115r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 116r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 117r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 118r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 119r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 120r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 121r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 122r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 123r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 124r REG 253,0 9281131 655486 /data/java/qqwry.dat
java 12025 tomcat 125r REG 253,0 9281131 655486 /data/java/qqwry.dat
發(fā)現(xiàn)大量打開qqwry.dat這個文件。
5、計算一下打開qqwry.dat的次數(shù)
[root@101 ~]# lsof -p 12025|grep "qqwry.dat" |wc -l
65212
打開65212次，讓開發(fā)的同學(xué)去查看與這個文件相關(guān)的代碼邏輯，發(fā)現(xiàn)這個類的邏輯里，只管打開文件，并沒有關(guān)閉文件的代碼邏輯，也就是打開了，并不關(guān)閉，而且每一次請求過來，就new一個這樣的對象出來，很明顯這樣的邏輯不妥。讓其不要每次都new一個對象了，建議改成單例模式。
上線后，再來看結(jié)果
[root@101 ~]# lsof -u tomcat |grep "qqwry.dat" |wc -l
1
哈哈，這個數(shù)量變成1了，爽歪歪:)
另外，發(fā)現(xiàn)一個博主寫的關(guān)于qqwry.dat的封裝類，在這里https://blog.51cto.com/binghe001/2924976，有需要的小伙伴可以參考
