Re: Linux mdadm superblock question.

[CaT <cat@zip.com.au>]

On Thu, Feb 11, 2010 at 05:52:41PM -0800, Michael Evans wrote:
> You need the superblock at the end of the partition:  If you read the
> manual that is clearly either version 0.90 OR 1.0 (NOT 1.1 and also

For lilo, at least, this is not so:

http://www.sfr-fresh.com/linux/misc/lilo-22.8.src.tar.gz:a/lilo-22.8/raid.c

Line 145:

if (ioctl(md_fd,RAID_VERSION,&md_version_info) < 0)

Line 155:

if (ioctl(md_fd,GET_ARRAY_INFO,&md_array_info) < 0)

Lines 160-168:

if ((md_array_info.major_version != md_version_info.major) &&
	(md_array_info.minor_version != md_version_info.minor)) {
    die("Inconsistent Raid version information on %s   (RV=%d.%d GAI=%d.%d)",
        boot,
              (int)md_version_info.major,
              (int)md_version_info.minor,
              (int)md_array_info.major_version,
              (int)md_array_info.minor_version);
    }

It's 0.90 or nothing as md_version_info gives 0.90 due to:

/linux/drivers/md/md.c:
Line 4599:

        ver.major = MD_MAJOR_VERSION;
        ver.minor = MD_MINOR_VERSION;

linux/include/linux/raid/md_u.h:
Line 23:

#define MD_MAJOR_VERSION                0
#define MD_MINOR_VERSION                90

I got bitten by this as I was testing different raid superblocks on a new
setup. Wound up hand-making my own initramfs, which was a pain (right pain
to debug). Would prefer not to have one tbh.

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