On Fri, Jul 25, 2014 at 12:32 PM, Benjamin Smith lists@benjamindsmith.com wrote:
On 07/25/2014 06:56 AM, Robert Nichols wrote:
Unless you can figure out some way to move the start of the partition back to make room for the RAID superblock ahead of the existing filesystem, the answer is, "No." The version 1.2 superblock is located 4KB from the start of the device (partition) and is typically 1024 bytes long.
https://raid.wiki.kernel.org/index.php/RAID_superblock_formatsSadly, this is probably the authoritative answer I was hoping not to get. It would seem technically quite feasible to reshuffle the partition a bit to make this happen with a special tool (perhaps offline for a bit
- you'd only have to manage something less than a single MB of data) but
I'm guessing nobody has "felt the itch" to make such a tool.
On 07/25/2014 08:10 AM, Les Mikesell wrote:
What happens if you mount the partition of a raid1 member directly instead of the md device? I've only done that read-only, but it does seen to work.
As I originally stated, I've done this successfully many times with a command like:
mount -t ext{2,3,4} /dev/sdXY /media/temp -o rw
But if you write to it, can you clobber the raid superblock? That is, is it somehow allocated as used space in the filesystem or is there a difference it the space available on the md and direct partition, or something else?