RAID: when will broken hard drive be noticed?
I run RAID 1 on our servers. As a test ( on a test machine), I pulled out the power from on of the mirrored disks while the system was running.
As you would expect (and as I expected and was releaved to see) the system didn't care. It just kept running.
However, when I looked at
# cat /proc/mdstat
it still showed that all the RAID devices were present. It wasn't until I rebooted a few minutes later, that the machine updated mdstat to show one of the HDDs was missing.
If I hadn't rebooted, does mdadm periodically check that both HDDs are still there (so taht it could hot add the replacement)?