How do I figure out my RAM requirements for Cloud Hosting?

I'm new to everything that is 'the cloud.'

I will be developing a website/platform that will have around 15,000,000 estimated monthly visitors after the first year of production.

I'm assuming that the site will have 5 page views per visitor, and 100kb of data transfer per page.

I've contacted several cloud hosting companies, but they tell me that I need to 开发者_开发问答have 'hardware requirements.'

Since I'm rather clueless about IT stuff, I'd like to know:

What are the factors that need to be analyzed in order to determine

• How many servers are required
• VPUs / server required
• RAM / server required
• Total storage / server required

Big thanks in advance!

I don't agree with the other answer as it's nearly total guesswork, as will anything you can generate yourself.

The only surefire way to know is to get some hardware, stick your application on it and run some load testing to see if you can get to the point you want to traffic wise, and with a certain amount of free overhead on the servers. Only then will you know what you need. No-one else can answer this question as every application is different. This is your application, only you can test it.

Data given wont help much in determining what numbers you want. But based on my experience I'll try to help you in analysis.

15,000,000 visits a month means 700K visits a day (assuming approx 30-35% visits are by repeat visitors).

700Kx5=3.5million page views a day. Assuming 14 hours of active period, typical for single timezeone sites. Its 70reqs/sec.

With this big userbase few thing you surely need is a high performance DB server, with one slave. Config of these DB server

1. Memory so that whole active data + indexes fits in memory (No swapping/thrashing should happen). This you need to calculate based on what you will be storing for user and for how long.
2. Use some reliable storage like RAID10 (higher read/write bandwith).
3. Take enough storage, see that its elastic enough. (like AWS EBS).

Make frontend app server lightweight and horizontally scalable. Put them behind a loadbalancer (use software loadbalancer like nginx or HAproxy). You should be able to put as many as you go to your goal.

For loadbalacer and frontend take 4CPU, 4-8GB RAM servers. How much each frontend can take need to be tested using a load testing method and realistic test data.

Reduce load on database/persistent using a inmemory/+persistent caches like memcached/membase/redis etc. Take a servers with 8GB and add more as you feel need.

I have not discussed about DB partitioning. Do that only when you feel the need of it. Do not over invest at start.

With 15M users a month, this setup should be enough, but again it all depends on you 1. memory footprint, 2. amount of active data

I tried to answer as much as possible. Comments on points you disagree or wanna discuss more.