I have a Windows 2008 Server with a two-drive software RAID 1 (mirroring). Last night one of the drives apparently failed (just disappeared from the system) and I had to boot from the secondary plex in order to get it running again. I don't know which of the drives actually failed as upon shutdown/restart both were online.
Now the Disk Management says the volume status is "Failed Redundancy". If I try to reactivate it, it starts resynching but apparently fails somehwere in the process as it encounters a bad block on one of the drivers (MIGHT be the other one).
I'm very confused now; I'm not sure at all what is the current state of the array - does Failed Redundancy mean it is still performing mirroring (there are no yellow triangles next to disks unless I try to reactivate them)?
And most importantly, I have absolutely no idea if the new data (the one that was created between last night and now) is contained on both drives or just one (which one?).
Any suggestions would be appreciated.
I have figured out which drive contained bad blocks, but unfortunately (of course, when things go wrong, they go really wrong) it was apparently the other drive that got dropped out of the mirror, so I had the latest data on the drive with bad blocks and no way to resynch the mirror as Windows really doesn't want to replicate data from a drive with bad blocks.
So after I made enough backups I decided to give it one more try (before cloning the drive offline) and tried an application called "HDD Regenerator", which is supposed to somehow "regenerate sectors which are not physically damaged but just incorrectly magnetized" (note that I don't fall for shiny interfaces of applications that are supposed to do miracles) and to my amazement in my case it actually somehow worked - no sectors were relocated and the data is still there. After running chkdsk with /B parameter to recheck (52 KB previously) the bad clusters it reported none were found, so I was able to successfully resynchronize the mirror and verified that all the data is intact.
Of course I will be very closely monitoring the drive (it passes all diagnostic tests now so I doubt I can return it) in the future and will toss it in the garbage at the next sign of abnormality.
Thanks for all the help.
UPDATE a year later
Still working perfectly with no bad sectors.