What are your thoughts on having all your sites on the same server? I have about 10 sites on one server and a few others dotted around. I do this as it works out cheaper. My only thoughts are, what if my server is hacked and malware uploaded - I'd be pretty screwed. What's your setup?
I personally prefer to keep my sites on various servers, VPSes and hosting accounts. I have a few VPSes, dedicated server and around a dozen shared hosting accounts and I distribute the websites accordingly. I personally like to keep my websites separate so that in case there is some problem with one server/hosting then I have other websites unharmed. It works out a lot more expensive for me but I feel more safer distributing my websites amongst various servers.
Having hosted on different machines lowers the risk only in theory. It is much better to have all the websites in one machine and to make sure it is properly managed, mirrored and backed up.
Its depends on your site and how important each sites. If you have blogs and not making a lot of money . Its good to go for single server. On the other hand, let say you have few ecommerce site and other database driven sites like social media then its better to go for multiple server. Let take a scenario. You host all 3 of your ecommerce site each making 3 to 10 sales per day and suddenly one day your server down or hacked and now at a time you need to restore 3 ecommerce server with lot of content. And also your backup will be 7 days (atleast 24 hours old) so you need to manually check your payment gateway for who all paid and those detail may not be available in your DB. Again this thing you have to do for 3 ecommerce site and also if the server down for long time you may look to host in new hosting provider in that its too horrible you need to transfer huge content of 3 sites there DNS and finally you need to manually login and check very thing work smooth in all the 3 sites after transfer to new host. so in those case better keep it in separate server. IF your server down in this case only one big site will need your attention
I think that is up only to you. I know some people not prefer keep all eggs in the same basket and some do.
It depends how big your sites are. I have about 10 personal sites, and they are hosted on 3 different servers at the moment. While I prefer "splitting" sites over different servers, I don't see any problems if sites are hosted on the same server.