Linux

We reboot our linux servers daily. Is it needed ?

Generally, no. Servers can operate weeks to months at a go, potentially years if it wasn't for kernel upgrades.

Often people do so because they see the value of "free" memory creeping very low and "cached" climbing very high, then reboot to forestall what they perceive as impending disaster. Many try putting strange settings into /proc/ to "flush the cache", as well. This isn't necessary, low free/high cache is normal operation, just count the value of "cached" in your estimation of free memory and usually everything is fine after all.

My experience is that virtual servers need to be rebooted more often than stand alone servers. Here is an example from one stand alone linux server:

Over two years since the last reboot .....

The only reason I can think of to reboot a linux server that often would be lots of crashed connections (those showing state FIN_WAIT or similar with netstat -an) preventing further connections to the server - and there may be a better way to fix that without reboot.
Were you told the reasons why your company reboots that often? What kind of application are those servers hosting?

We run a stand alone java application with Database.

Description
1. Stand alone web application run in apache tomcat 6..
2. A database connection in postgresql 8.3..

System configuration
CentOS 5
~ 4 to 8 GB of Ram , (Differ in each servers)
core 2 duo processor
Java 1.6 [Oracle]

Users per server
~ 100 - 200 sessions.

But daily needs to reboot..

It doesn't likely need to reboot. What ISSUE are you experiencing? Rather than telling us you reboot, tell us the problem, not some workaround you found.

mark,

The application runs is not a small one. it's a big application. And the server becomes very very slow as it used from morning to evening..

Thus in some servers tomcat / postgre or the Entire system itself reboots.