Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

A simple scenario , I have implemented a Email server for my users to access / send emails . Now the users have grown and my server is not able to handle the load .

Now the question is why does a simple thing like email create a server load ?

Scenario 1) It has reached its network limits - bandwidth ( this can be fixed by askig ISP to give me more bandwidth so ruled out) or TCP/IP ports - max 64000 per server is only allowed if I am not mistaken . I reckon this possibility is more relevant . What would be a solution then ? Add more network cards and enable bonding ? If yes will the bonding take care of load balancing ? Again only 1 IP so how can this counter this problem ? Maybe Virtual IP's ?

Scenario 2) It is not able to process requests - (Processor not enough ). Now the solution is probably Clustering . How do I go about implementing this? Who takes care of load balance ? Would it be like 4 servers each having webserver package running with a IP ?

share|improve this question
This is not a problem I have currently , but a likely scenario that I can come up with in Adminisrtation of large servers. – Nishant Mar 7 '11 at 14:08
up vote 3 down vote accepted

Considering your knowlege level you should find someone who knows what they're doing to evaluate your system and recommend upgrades or ways to improve efficiency.

Scenario 1a - Network bandwidth saturated. This is quite unlikely. You didn't mention anything about why you think there is a problem, but e-mail tends not to be bandwidth heavy unless you have a very large organization, and even then other factors of the system tend to be the bottleneck first.

Scenario 1b - Out of Ports. No, it doesn't work that way. Not even close.

Scenario 2 - Processor Capacity. This is more likely the issue, it also could be RAM, Disk Space, Disk Speed (throughput/latency), or something else entirely. Clustering is one potential option. A load balancing hardware device or specific software distributes connections; though you'll typically get more benefit from distributing the load intelligently by roll and/or destination.

Mail servers are not web servers, that's something else entirely. Computers must have IP addresses to work on the Internet; what kind of address will depend on your design.

share|improve this answer
+1 for that opening comment; SF is not a substitute for years of IT experience. – MadHatter Mar 7 '11 at 13:55
Thanks I am basically asking this to enhance my knowledge and also others who have less experience . Why does the TCP/IP 64000 ports not be a problem ? – Nishant Mar 7 '11 at 14:07
TCP connections (which aren't the only type that use ports) keep track of connections based on Source IP, Source Port, Destination IP, and Destination Port. Assuming your server as 1 IP, 1 Port open, and unlimited capacity for processing connections: 600 Million PCs on the net * 63,000 Ports each (first 1k are reserved) * 1 (Your IP) * 1 (your Port) = ~38 Trillion possible connections. In case nobody has pointed it out yet, this site is For IT Professionals only, please see the FAQ for more details. – Chris S Mar 7 '11 at 14:28

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.