RAID is to decrease the odds of downtime in the event of a disk failure. It is NOT a "backup" in any sense. A backup strategy should always be implemented independent of the RAID array.
It sounds to me, with a single disk failure, that your data is still there and you simply need to repair your damaged OS, but it just feels like there is too little information on what happened and your config to be able to say that with confidence.
Thank you THEFLASH1932,
let me know how to fix it the OS, cause i can't jump in OS, it still blank page after booting. is it simply that i just remove the failure hardisk and replace it with new one? after i change it, should i repair my OS? is it dont change any data that i have? need your guidence please
Thank you before