I wonder if the company (Santrex.net) has DCs in different locations, how does it influence the performance of servers if their clients aren't in that location where the DC is?

Different datacenters, different stuff and different network providers - there are many differences. I think that support only have no differences.

It will influence the speed but in a very non-noticeable way.

Thanks

I would never put all my servers in the same DC. Asking for trouble I think. All eggs in one basket kinda thing

It depends on your business model. If you rent servers fom vendors, you can choose different vendors in different areas. If you colo your own hardware, you would like to choose a good colo vendor, and put all your stuff there - easier to control, save cost. Of course, running off-site server for your status site would be a great choice. So if the main datacenter has trouble, you will still have a place for updating for your customers.

It's always smart to pick a data center which is physically closer to your location or closer to your targeted audience.
It's nice to have bgp loadbalanced servers at multiple location if you're running something mission critical for greater speeds and availability.

DC location is important when your clients are from particular geographic area. It's also useful to get higher ranking for your website.

Multiple DataCenters is something that can be a great benefit in your business model. We're using 8 different centers at the moment, 6 of which are owned by the same company. The physical location difference is great for being able to target certain locations and keep speeds fast for users and their intended audience.

The disadvantage however is often you are often dealing with different data center companies, and as a result since you're a "small fish in a big bowl" you don't get the discounts that you'd hope for.

Keeping equipment and clients in different parts of the country/state/world means that a natural disaster in one location will not cripple your business should things go offline for a few hours or a day in an emergency.

there are always pros and cons in spreading your DC. For me, I opt for the geographical DC. I do not like to put all my eggs into one basket...you know the risk