I have a simple 3-HDD RAID-5 system, at home, that is currently controlled by my motherboard rather than a seperate RAID controller. Recently I have been getting I/O errors when moving files around and suspect the controller. I've been told that if I insert a PCI controller, that I won't be able to read any of my files, because RAIDs are specific to the controller that they were set up on.
This is a situation of YMMV (your mileage may vary).
Contact the company whose controller you are thinking of purchasing and tell them you have a RAID array (with specifics of motherboard) and ask them if they will recognize that array.
In the OLD days, even a newer model of an Adaptec (one of the biggest and best at the time) controller would not recognize the array of an older model! (requiring a backup/restore to upgrade/replace - bad news!)
Then (Adaptec, anyway) standardized so that arrays were NOT model specific.
But I certainly cannot speak for all companies.
So yes, it was that way and I would certainly check FIRST before buying.
Thank you for responding. I've spoken to several of my "techie" friends and they have stated very similar statements. It does seem grim, but I am holding out hope until the last. I'll post if I get good results.