need help to solve big lag in bukkit CB 617

all my server works perfectly with bukkit cb 531 with same plugins of cb 617 and 40+ players online, with cb 617 after 20minuts server got a big lag and randomly disconnect all the player!

my plugins list:

BigBrother with mysql
Worldguard
WorldEdit
iConomy
iConomychestShop
MessageTimer
autosave
Authme
Netstats
CookieMonster
iChat
Permissions
Essentials
Bukkittcp for webbukkit

CB:617

hardware:

i7910
16 gb ram ddr3 ECC
2 tera hd radi 0,1
200mbit frankfurt
linux ubuntu server 64 bit

java jre 1.6

my start.sh:
screen -wipe
screen -AmdS minecraft java -server -Xmx2000M -Xms256M -XX:+UseConcMarkSweepGC -XX:+UseParNewGC -XXarallelGCThreads=4 -XX:+CMSParallelRemarkEnabled
-XX:+DisableExplicitGC -XX:MaxGCPauseMillis=500 -XX:SurvivorRatio=16 -XX:TargetSurvivorRatio=90 -jar craftbukkit.jar nogui

i have to stop and restart server everyhours its very bad.. got 30+ players online.. and with same plugins 0 lags with cb 531! someone have some advice to solve this problem?

 

Try removing those java flags and use only -Xmx2G

 

try it... nothing change.. server crashed 2 hours ago.

try to replace bigbrother with logblock... i extend life time of my server but after 20+ player all got laggy and unplaybale!