Mounting multiple devices at a single mount point on Linux

Is there a way to mount multiple hard drives to a single mount point? Let’s say I run out of space on /home and decide to add an extra hard drive to the computer. How do I scale the space on a mount point? If I use RAID, can I add drives on the fly to increase space as I run out of them? Is there an alternative to using RAID if I am not interested in maintaining a high level of redundancy?

bit rot detection and correction with mdadm

I’m about to re-organise all my HDDs in my home linux box nas and would like to use mdadm raid for data protection and its flexibility for reshaping the arrays. However, before I use mdadm for this I’d like to know how it handles bit rot. Specifically the kinds of bit rot that do not result in unrecoverable read error messages being sent from the HDD.

Linux raid disappears after reboot

My troubleshooting ability in Linux is not impressive, just so you know. I can follow instructions very well on the other hand. I have a Linux server with Linux raid. It was working well with no problems for about half a year but then I had a power failure and have been getting the same problem ever since. After rebuilding the raid all my files are still there, so that’s a good thing. When I reboot the server the raid device md0 is gone.