I've two exchange server, one in each of location, I'd like to have email receive never failed that if one site is down, the other will get all those email and pass it back to the down server when it's up and running again. each of the server will hold different users' account.

I don't mind if users cannot access to his/her mailbox if the home server is down.

But if there's solution that can solve this issue will be good.

Your help would greatly be appreciated. Thank you.

What you need is site resilient Exchange 2013 deployment. It can be done, but it's not an easy setup. Before you consider that I strongly recommend that you read this article: http://technet.microsoft.com/en-us/library/dd638137(v=exchg.150).aspx

Thank you Damir, I'll take alook at that. ^_^