Linux Software RAID: How to fsck on hard drive

Your dmesg output should give you an indication as to why it's signalling failure to the PV; that shouldn't be happening. As far as getting the system writable again, kicking the VG and LV to read-only and then back to read-write works from memory, but the real resolution is getting md to stop worrying LVM unnecessarily.

For anybody else who ends up suffering the error 15 grief that I did, it turns out that the device naming scheme in grub (hd0, hd1, hd2...) ended up being different between when grub boots and when grub is running after the system is up and running. I spent a week with root (hd2,0) because that's what grub told me the drive I wanted was called. But when I dropped to the grub shell on bootup I was surprised to find out that what was hd2 when the machine is up, is hd1 on boot. So I changed the menu.lst to use root (hd1,0) and it started working. I hope to save somebody else lots of hair pulling with that one.