Outlook strikes again

For two days, Outlook strikes again. In our scenario, we configured Outlook to save the PST files to the network file server; so that we can have a better centralized backup. However, if a smallest problem happens with the File Server or the network connection, it takes a very long time for the users to open their Outlook PST files :-(. It concidentally happened that the network cable of the File Server was loose for less than 3 minutes, but it took two days for the users to recover :-(.

I don’t really understand, why there is no mail client with RDBMS technology so it is pretty simple to do the centralized backup. Is it really worth to write one by ourselves ?? If you are aware of such mail client, please kindly inform me for further evaluation.