proftpd 在達到一定數量的程序後鎖定

我們有一個在 centos6 上執行的 proftpd 伺服器（1.3.3g），當它似乎超過大約 150 個正在執行的程序時，它會鎖定並阻止更多的連接。

proftpd 伺服器連接到 MYSQL 以處理使用者身份驗證。

我已經執行了 proftpd 偏執日誌，並且看不到任何失敗，並且檢查了安全日誌中是否有任何登錄失敗，並且沒有任何問題。

監控顯示在它跌倒期間沒有 CPU/記憶體/磁碟/網路峰值，它似乎只是鎖定，直到連接再次下降。該機器應該可以處理超過 150 個並髮使用者（E3-1271v3 32GB RAM）。

PROFTPD 配置

# This is a basic ProFTPD configuration file (rename it to
# 'proftpd.conf' for actual use.  It establishes a single server
# 'proftpd.conf' for actual use.  It establishes a single server
# and a single anonymous login.  It assumes that you have a user/group
# "nobody" and "ftp" for normal operation and anon.

ServerName                      "PROHIBITED FTP ACCESS"
DeferWelcome                     off
#ServerType                      standalone

# Globbing
UseGlobbing off

TransferLog /var/log/ftpxferlog
UseReverseDNS off
IdentLookups off
UseFtpUsers off 
WtmpLog off
UseIPv6 off


# Restrict the range of ports from which the server will select when sent the
# PASV command from a client. Use IANA-registered ephemeral port range of
# 49152-65534
PassivePorts                    49152 65534

Port                            21
Umask                           022

TimeoutLogin                    120
TimeoutIdle                     300
TimeoutNoTransfer               300
TimeoutStalled                  300

# Default to show dot files in directory listings
ListOptions "-a +R" strict
# ListOptions "" maxdepth 3
# ListOptions "" maxdirs 10
ListOptions "" maxfiles 2000
AllowOverride off

# Set the user and group that the server normally runs as.
User                            www
Group                           www

# Set path locations
ScoreboardFile                  /var/run/proftpd.score
#DefaultRoot                    /data/filesroot/ftproot/pub
DefaultRoot                     /data/filesroot/ftproot

# Log formats
LogFormat                      default "%h %l %u %t \"%r\" %s %b"
#LogFormat                      anonymous "%h %l %u %t \"%r\" %s %b"
#LogFormat                      auth    "%v [%P] %h %t \"%r\" %s"
#LogFormat                      write   "%h %l %u %t \"%r\" %s %b"

# SQL authentication Dynamic Shared Object (DSO) loading
# See README.DSO and howto/DSO.html for more details.
<IfModule mod_dso.c>
  LoadModule mod_sql.c
  LoadModule mod_sql_mysql.c
  LoadModule mod_ifsession.c
</IfModule>

# Global settings
<Global>

       AuthOrder               mod_sql.c

       SQLEngine               on
       SQLAuthenticate         users groups
       SQLConnectInfo          xxx@xxx:3306 USERNAME PASSWORD
       SQLAuthTypes            Backend
       SQLUserInfo             ftpusers username passwd uid gid NULL NULL

       SQLDefaultHomedir       /data/filesroot/ftproot/

       RequireValidShell       off
       SQLGroupInfo            ftpgroups groupname gid members
       SQLDefaultGID           65533
       SQLDefaultUID           65533
       SQLMinID                350

       ServerIdent on "FTP Server ready."
       AllowOverwrite          yes
       IdentLookups            off
       DelayEngine             off

       # Logging
       # file/dir access
       #ExtendedLog            /var/log/proftpd/access.log WRITE,READ

       # Record all logins
       #ExtendedLog            /var/log/proftpd/auth.log AUTH

       # Paranoia logging level....
       #ExtendedLog            /var/log/proftpd/paranoid.log ALL
</Global>

<Limit LOGIN>
     Order allow, deny
     DenyAll
</Limit>

# Deny writing to the base server...
<Directory /data/filesroot/ftproot/pub/*>
   <Limit WRITE>
   DenyAll
   </Limit>
</Directory>

<Limit WRITE>
DenyAll
</Limit>

<Directory />
       HideNoAccess on
       <Limit WRITE>
       DenyAll
       </Limit>
</Directory>


<VirtualHost xxx.xxx.xxx.xxx>

       ServerAdmin             xxx@xxx.com
       ServerName              "FTP"

       DefaultRoot             /data/filesroot/ftproot
       SQLDefaultHomedir       /data/filesroot/ftproot/

       TransferLog             /data/logs/ftp/files/files.xferlog

       RequireValidShell       off
       AllowOverwrite          on
       AllowRetrieveRestart    on
       AllowStoreRestart       on
       MaxLoginAttempts        2
       MaxClients              2000 "Sorry, maximum users reached."
       MaxClientsPerUser       5
       MaxHostsPerUser         2

       # How quickly do we kick someone out?
       TimeoutLogin            45
       TimeoutIdle             15
       TimeoutNoTransfer       300

       # Port 21 is the standard FTP port.
       Port                    21

       # Umask 022 is a good standard umask to prevent new dirs and files
       # from being group and world writable.
       Umask                   022

       # Set the user and group that the server normally runs at.
       User                    www
       Group                   www

       # Set Anonymous access controls
       <Anonymous /data/filesroot/ftproot/pub>
               User                    www
               Group                   www
               UserAlias               anonymous www
               RequireValidShell       off
               MaxClients              1

               <Limit WRITE>
               DenyAll
               </Limit>
               # Don't write anonymous accesses to the system wtmp file (good idea!)
               WtmpLog      off
       </Anonymous>            

</VirtualHost>

---

對於 FTP 伺服器來說，150 個並發連接似乎非常小。任何見解將不勝感激

問題原來是數據庫表是 MyISAM 而不是 InnoDB，所以當它忙時，整個表鎖定會導致級聯效應。將這些表更改為 INNODB 解決了這些問題，因為它現在只鎖定行。

引用自：https://serverfault.com/questions/949455