When attempting to test that my RAID-1 configuration was working, I am thinking that I may have made a mistake that could cause future corruption of data because I booted from a single HDD when the other was off.
I have a SATA RAID 1 array set up on my Ubuntu 10.04 machine which I believe is using fakeraid with dmraid to map the disk array into a single filesystem). To test that my RAID-1 config was working, I unplugged one of the SATA drives when the machine was off and started the machine up.
During startup of the BIOS, the computer issued a complaint that one of the disks from the array was missing - as expected. During the linux boot, it seems that dmraid was not mapping the RAID array under /dev/mapper/ because the second disk wasn't detected, and I wouldn't get past initramfs. To get around this, I rebooted and changed my GRUB options to start up linux using the parameter "root=/dev/sda1" instead of "/dev/mapper/" to boot directly from the disk that was still plugged in.
I rebooted and booted into Linux fine - immediately turned the machine off, plugged in the other disk and booted up with both HDDs enabled - RAID back on and original boot arguments set to use /dev/mapping/".
Everything seems to be working fine, but I'm worried there could be some problems down the road if something got written to disk during the boot when /dev/sda1 was being explicitly used.
Is there any way I can verify integrity of the RAID-1 array between the two disks? I tried doing an fsck but it complained that I was using a mounted filesystem and that this was a no-no. Any ideas?