On Fri, Jul 25, 2014 at 12:32 PM, Benjamin Smith <lists at 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_formats > > Sadly, 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? -- Les Mikesell lesmikesell at gmail.com