Answer is not easy and for every installation it can be different. I will try to suggest you way how you should compute it.
What we know:
- highest traffic on server will be generated from requests registering impressions of your banners on sites of your affiliates
- on common computer with 2.4GHz with 3GB or RAM is possible to execute about 20 requests per second. More CPUs you will have and more RAM you will have, you can execute more requests per second.
- On hard drive PAP require about 50-60MB of disc space - we recommend minimum 100MB of disc space to have free
Now you need guess number of impressions your affiliates will generate per second on their sites:
number of impressions you can compute in following way:
number of impressions = number of affiliates in your program * Avg. number of page views of your affiliates site
e.g. you have 1000 affiliates and each has page with daily traffic about 1000 page views
It means you will need to handle per day about 1 000 000 requests coming from registering of impressions. It means about 11 requests per second (1 000 000 / 24 / 3600).
Next to load coming from impressions you have to count also with load generated by other operations in PAP and also by load generated by other applications installed on your server.
How to choose right server now ?
To add just more CPUs is not enough to handle higher loads on server.
You will need also to add more memory (RAM), because in same second will run in memory more processes and each process needs some memory
How much memory is needed per request depends on compilation of your php and Apache - how much modules and extensions is used and so on - in average you can count with something between 5 - 20 MB per request
Even if you have a lot oc CPUs and memory, botleneck can be speed of harddrives. We recommend to use SCSI drives or raid arrays with stripping on your server.
What could help to improve performance of existing server ?
- You can use php cache to improve load time of php scripts. Example of such cache is eAccelerator, which can be compiled on hosting accounts with cpanel automatically without any extra effort in WHM panel
- If main problem is load in your Mysql, we recommend to upgrade to Mysql 5.1 and partition tables, where is highest traffic by key
- check if your Apache and PHP compilation use just modules/extensions you need for your web sites - by reducing number of loaded modules and extensions you can reduce amount of memory required for each process/request (if you have e.g. 20 requests each second on server, this optimization will reduce amount of required RAM and your server will be able to handle more requests per second as before)
- distribute files touched every second through more hard drives - e.g. Mysql data move to drive 1 and php files on another drive
Recommendations
Start small and upgrade to more powerful servers when you will see, that server is overpowered or runs on 75%.
It has no sense to buy huge server when you plan to have up to 50 small affiliates.
Sometimes also one affiliate can generate so big traffic, that your server will crash - keep this in mind and think about it.
If you plan to add your banners e.g. on any community site, where can be few millions of impressions per day, upgrade your server before you will hire such affiliate.
If server is overpowered by traffic comming from PAP4, please contact us.
We can review it and suggest improvements directly for your server.
Often small changes can help to resolve it without upgrading of server.
Which hosting company to choose ?We can review it and suggest improvements directly for your server.
Often small changes can help to resolve it without upgrading of server.
Hardware is in every hosting company similar, but main differences are in offered support.
We have very good experiences with support crew of Liquidweb.
During last 4 years we had from them multiple servers and we had never any hardware failure yet.
Their Heroic support team has response time about 30 minutes and you can always rely on them.
They offer solutions for low traffic website as well as high performance servers joined into server farms, so everyone can choose right size.