How transfer is charged?

January 5, 2014 5.2k views
Hi, I have a question about transfer charging. If I buy 4 droplets of 5USD each one having a transfer of 1TB Transfer I will have to pay 4 x 5 = 20 USD monthly. Those 4 droplets will name A, B, C i D. Here is deployment layout: /----- B / A ------- C \ \----- D On A is load balancer and on B, C & D are web servers. Droplet A is only one accessible from outside. Imagine I have 3TB transfer via A. 1TB is distributed via AB, 1TB via AC and 1TB via AD. How I will be charged? I have 4 droplets each of 1TB transfer which in total is 4 TB but on the other side droplet A come with 1TB only. Can I count on $TB transfer in this situation or only 1TB? If interdroplet transfer is not charged how this relates with total transfer? Does those 20USD are enough for this month and 3TB or transfer or I will be charged for 2TB above on droplet a? Best, Dragan
8 Answers
According to the Pricing page, "only outbound transfer is counted" toward your droplet's quota.
but in case above if we have 4 x 1TB droplet does this mean that total outbound quota is 4TB and that all 4TB traffic can pass via A droplet without extra charge?
DigitalOcean will not pool transfer caps across all droplets in an account. Each droplet will have its individual transfer cap.
Is intra droplet traffic classed as outbound traffic?

2 droplets
A is a webserver
B is a mysql server

Client connections to A
A requests data from B
B returns data to A
A renders page and responds to client
As long as it's on the public interface, yes. You can utilize private networking so that you are not charged for outbound traffic.
by Etel Sverdlov
Here's documentation on how to set up and use DigitalOcean private networking.
in other words this mean that I will have to pay for additional 2TB?
In my case all outbound trafic is via droplet A so I will be charged for 2TB over?
  • What architecture do you suggest for a high traffic website? (See my comment below)

I think the Digital Ocean platform would be a lot more attractive to high traffic architectures if the sum of all droplet-transfer could be added up to a total. Where this total transfer is consumed shouldn't matter.

Say for example I have a high traffic site that needs 8 webserver droplets of 1GB that serve the webpages (internally). An in front of those I'd need a load balancer droplet of 1GB that distributes the incoming requests over the webserver droplets.

So all public traffic goes through the load balancer droplet, all communication from and to webservers is internal traffic and doesn't count towards the cap.

Now my total public the website can serve is 2TB (since the cap of the load balancer is the only one useable). While my webservers could easily handle the needed 15TB for running my website.

The current droplet models would not even allow me to use Digital Ocean since the maximum cap is 9TB, and paying for this unneededly big machine plus the 6TB extra traffic is unattractive.

Alternative would be to us DNS load balancing but that is undesirable because of the inflexibility and dependence on how clients handle receiving multiple IPs for a name.

How would you architect a high traffic website on Digital Ocean? Maybe I'm just overlooking some options :-)

Regards, Jacco

Have another answer? Share your knowledge.