correct... the problem was that server rebooted a few times and probably the filesystem got damaged... we don't know... but that's life. I heard there are other hosters that don't use any RAID or just RAID0 what is useless in case of a crash...
But you must understand if you have a server with e.g. 50TB you can only use 25TB in RAID1. So it's all about the money... Who will spend 25TB just for data protection?
25TB is much! So if you use the full 50 TB in RAID0 you have the double amount of data storage and you can safe a lot of money... But it's not worth it to lose customers files just for better speed...
It's not easy to decide if you choose data protection in this business because it's very expensive as you just have half of the servers storage space for your users...