Me and my friend were discussing this the other day about how he said RAID is no longer needed. He said it was due to how big SSDs have gotten and that apparently you can replace sectors within them if a problem occurs which is why having an array is not needed.
I replied with the fact that arrays allow for redundancy that create a faster uptime if there are issues and drive needs to be replaced. And depending on what you are doing, that is more valuable than just doing the new thing. Especially because RAID allows redundancy that can replicate lost data if needed depending on the configuration.
What do you all think?
This has nothing to do with ssd or their size. Harddisks also have a little spare area (though not as big) and can mark and remap failing sectors.
RAID (1) is still (possibly) good for the only thing it ever was (possibly) good for: Keeping the system running long enough for you to put in a new harddisk if one fails.
Think of industrial systems where every minute of downtime can cost thousands of dollars. And even there the usefulness of RAID can be questioned: should you not in that case have a whole spare system, easy to swap in, because more than just storage can fail?
And what about the RAID controller itself? Does it not add complexity and another point of failure to the whole system?
And most importantly: will anyone actually get notified of a failing disk and replace it quickly? Or will the whole thing just prolong the inevitable?
Would you even trust a system that had one disk fail already to keep going in a critical place? Or would it not be safer to just replace the whole thing anyway after one failure?