Concurrent users calculation

Hi guys,

I needed some help in calculating how many concurrent users and connections my website can handle before it is finally launched and I invest money in bandwidth and hardware..

(Site will be hosted in-house)

Homepage size: Around 49KB
Website will have user registration kind of thing, adding comments, viewing articles and so on.. so a lot of read and writes to the MYSQL database
WAN connections – Dual WAN (2Mbps each) so totals 4Mbps(megabits per second)

I am expecting roughly around 70,000 to 80,000 hits every day initially.

Will this kind of internet connection be able to handle this traffic?
How can I calculate the maximum concurrent user connections I can have on my website?

mysql and webserver specs will also be provided if requested.

Regards,

Assuming each user is just going to visit your homepage, here are some basic calculations:
Homepage size = 50 KB = 400 Kbits
Connection bandwidth = 4 Mbps

75000 hits per day = 0.868 hits per second
Required bandwidth = 0.868 x 400 Kbps = 347 Kbps
So you can easily sustain those many hits a day.

As for concurrent users, 4 Mbps can handle approximately 10 requests per second of 400 Kbits each. From a server standpoint, 10 requests/sec is quite low and just about any home PC can handle this amount.

Remember that these calculations are just for the homepage. You should scale the values accordingly if you expect each user to visit several pages.

Hi casablanca,

Thanks for the response and detailed explanation.
Just one more query -

I was looking at one side .. like users just hitting the homepage..
Let's say now that -

website is sending automated emails to users for activation
users are registering on the website
posting comments
making posts and so on

Do you think 4mbps would be sufficient for all of this?
And around 100s of users doing the above simultaneously..

Regards,

By the way -

Server specs are as follow if you are interested

2 SQL servers - 3 GB memory
master and slave replication

2 webservers - load balanced

It depends on what amount of each activity you expect. For example, how many user registrations per day and how many posts per day?

Also, how do you define "100s of users simultaneously"? If 100 users just open up your page and read through it for an hour, it's just 100 requests for that hour. But if they're continuously navigating between pages, that would be many more requests.

As I mentioned in the first post, your server is probably not going to be the bottleneck. In fact, a single PC can handle all the activities you mentioned quite easily.