1. Webアプリケーションとメモリ
JVM Operation Casual Talks
2014/04/07
長野雅広 kazeburo

2. LTだけど自己紹介
• 長野雅広 Masahiro Nagano
• @kazeburo
• Perl Monger
• Operations Engineer, Site Reliability
• LINE Corp.
Development support
on LINE Familly, livedoor

3. Javaは1行も書いた事ない

4. Javaなアプリケーションを
運用したことはあります

5. GCで苦労した話やJVMの
チューニングの話は他の方が
すると思うので、Perlな
Webアプリケーションの
メモリ周りの運用の話をします

6. Perlの普通のWebアプリケーション
実行環境
• mod_perl
Apache HTTP Serverにperlインタプリタ
を組み込んだもの。古代から存在
• Starlet, Starman
Perlで構築されたWebアプリケーション
サーバ

7. 特徴
•Multi Process / Prefork
•MaxRequestPerChild

8. 親 Worker
accept
Worker
accept
Worker
accept
Worker
accept
bind
listen
fork(2) fork(2) fork(2) fork(2)
Client Client ClientClient
Multi Process / Prefork
CoW によるメモリ共有もされる

9. MaxReqsPerChild
accept
accept
accept
accept
accept
accept
accept
accept
exit
life time
of process
fork

10. exit/fork burstborn
exit
born
exit
born
exit
born
exit
born
exit
born
exit
born
exit
born
exit
born
exit
born
exit
born
exit
born
exit
service start
bornbornbornborn

11. exit/fork burstborn
exit
born
exit
born
exit
born
exit
born
exit
born
exit
born
exit
born
exit
born
exit
born
exit
born
exit
born
exit
service start
bornbornbornborn
HIGH LOAD HIGH LOAD HIGH LO

12. bumpy lifeborn
exit
born
exit
born
exit
born
exit
born
exit
born
exit
born
exit
born
exit
born
exit
born
exit
born
exit
born
exit
service start with --max-reqs-per-child=# --min-reqs-per-child=#
randomize lifetime of processes
born
born
born
born

13. process life & memory usage
born
exit
usage
time
大容量のメモリ確保
循環参照によるメモリリーク

14. process life & memory usage
born
exit
born
exit
born
exit
born
exit
born
exit
born
exit
born
exit
born
exit
born
exit
born
born
born
usage
time
通常のメモリ使用量

15. Multi Process / Prefork,
MaxReqsPerChildな
アプリケーションの運用
• MaxReqsPerChildによりメモリが確実に解放さ
れるので、一時的に大きなメモリ領域を確保し
たり、メモリリークの許容ができる
• イレギュラーなメモリ使用量の増加を
見つけて対応する

16. 運用で対処ってやつ
最近ではアプリケーションサーバでは Hot-Deploy もできるので
サービスに影響させずにコード変更・設定変更ができる

17. それ、JVMだと
どうなるの？？
どうしてんの？？

20. 参考にさせて頂きます
ありがとうございました