I found the answer.

Spaces have the following request rate limits:

750 requests (any operation) per IP address per second to all Spaces on an account

150 PUTs, 150 DELETEs, 150 LISTs, and 240 other requests per second to any individual Space

2 COPYs per 5 minutes on any individual object in a Space

Spaces, in my experience are not high speed storage devices. Think of a space as a hard drive, and you read and write to the hard drive via url. Think of it as a website with no webpages other than links to files. Click on the link and download the file. This is a simple description and it can get complicated, but this is the basics. No thinking this is what you are looking for.

Is there any one can explain me what is “750 requests (any operation) per IP address per second to all Spaces on an account”

And why there is'PUT’ limit per second. When my application gets bigger those limits are not usable.

If i use spaces as image storage for my news site and if i have more than 750 visitors per second then my visitors cant access images. Is it right.

Hi there,

For query cache, I would recommend sticking with Redis. You could also run Redis on your Droplet directly:

https://www.digitalocean.com/community/tutorials/how-to-install-and-secure-redis-on-ubuntu-18-04

I would use Spaces for static files like images and etc.

Hope that this helps!
Regards,
Bobby