Hi, I am running Redhat enterprise 7. I have disks configured for mirroring in RAid 1. If my primary disk failed, does the operating system know how to fail over and use the mirrored disk? What are the correct steps to temporarily use the mirrored disk, until I can find a replacement for the primary failed hdd.?
thanks

This article gives decent example of mdadm sw-raid breaking mirror... Need to break md RAID1 configured root partitions and boot the system from each individual MD RAID leg.

Please note this is not recommended for production, but provided as reference to learn/use to become familiar in a controlled test environment on non-production equipment. I encourage you to play with it first in a test VM that might be similarly configured, so that you won't need to worry about making mistakes with it.

If you are working with a hardware RAID controller then it should be abstracted from RHEL7 and it only has the notion of a single [virtual|logical] disk that the controller presents to the OS regardless of the number of component [physical] disks comprising what the RAID controller presents. Or, if using LVM mirroring, the process will be slightly different than the article provided above demonstrating mdadm raid1.