Changes between Version 11 and Version 12 of jazz/Performance_Tuning

Timestamp:

May 11, 2010, 3:49:21 PM (15 years ago)

Author:

jazz

Comment:

--

jazz/Performance_Tuning

@@ -14 +14 @@
 == System Performance Tuning : File System ==
 
- * /etc/security/limits.conf - 每個程序(process)可以開啟檔案的個數(number limits of open files per process) - 像 HDFS 的 !DataNode 就需要調整這種參數([wiki:jazz/10-02-22#Hadoop:HDFS 2010-02-22])
+ * 如何調整每個使用者可以開啟的檔案個數
+   * [參考] [http://www.xenoclast.org/doc/benchmark/HTTP-benchmarking-HOWTO/node7.html Increasing the file descriptor limit]
+   * [參考] [http://www.netadmintools.com/art295.html GNU/Linux - How Many Open Files?]
+   * 注意：修改 /etc/security/limits.conf 中間必須確定是 TAB ，如果有設定 vim 的 softwaretab 的話，得特別當心!!!
+   * /proc/sys/fs/file-max - 核心預設最多可以開啟的檔案個數
+{{{
+~$ cat /proc/sys/fs/file-max
+743964
+}}}
+   * /proc/sys/fs/file-max - 目前已開啟檔案個數、可供開啟檔案個數、總開啟檔案上限
+{{{
+[root@srv-4 proc]# cat /proc/sys/fs/file-nr
+3391    969     52427
+|        |       |
+|        |       |
+|        |       maximum open file descriptors
+|        total free allocated file descriptors
+total allocated file descriptors
+(the number of file descriptors allocated since boot)
+}}}
+   * /etc/security/limits.conf - 每個程序(process)可以開啟檔案的個數(number limits of open files per process) - 像 HDFS 的 !DataNode 就需要調整這種參數([wiki:jazz/10-02-22#Hadoop:HDFS 2010-02-22])
 {{{
 #!diff
@@ -23 +43 @@
  #@student        -       maxlogins       4
  
-+*      soft        nofile        8192
++*      soft        nofile        4096
++*      hard        nofile        743964
 +
  # End of file
 }}}
- * [參考] [http://www.xenoclast.org/doc/benchmark/HTTP-benchmarking-HOWTO/node7.html Increasing the file descriptor limit]
+   * /etc/pam.d/login - 告訴系統要用 /etc/security/limits.conf 來設定一些上限
+{{{
+# Sets up user limits according to /etc/security/limits.conf
+# (Replaces the use of /etc/limits in old login)
+session    required   pam_limits.so
+}}}
+   * 指令: ulimit - 可以告訴你一些系統限制，並且設定想要的値
+{{{
+jazz@Wdebian:~$ ulimit -a
+core file size          (blocks, -c) 0
+data seg size           (kbytes, -d) unlimited
+scheduling priority             (-e) 0
+file size               (blocks, -f) unlimited
+pending signals                 (-i) 72704
+max locked memory       (kbytes, -l) 32
+max memory size         (kbytes, -m) unlimited
+open files                      (-n) 1024
+pipe size            (512 bytes, -p) 8
+POSIX message queues     (bytes, -q) 819200
+real-time priority              (-r) 0
+stack size              (kbytes, -s) 8192
+cpu time               (seconds, -t) unlimited
+max user processes              (-u) 72704
+virtual memory          (kbytes, -v) unlimited
+file locks                      (-x) unlimited
+}}}
+ * 假設 /proc/sys/fs/file-max 跟 /etc/security/limits.conf 都有設定上限為 743964，且 /etc/pam.d/login 也有打開，但是 ulimit -a 指令仍顯示 1024 (預設)，可以修改 /etc/rc.local 或 /etc/profile 強制用 ulimit -n 743964 來提高開檔個數。
+{{{
+~$ ulimit -n 743964
+}}}
+ * [備註] 如果 ulimit 超出可容許範圍，會顯示 Operation not permitted，此時請檢查相關設定値
+{{{
+~$ ulimit -n 7439640
+-bash: ulimit: open files: cannot modify limit: Operation not permitted
+}}}
 
 == I/O Performance Tuning : NFS ==