Hello Wilson,

Thanks a lot for your answer. The issue is now solved, actually.

Majordomo refused my previous post, again! :( ... when I inform it was
solved.
[ It's really annoying this thing to have to remember to force messages
as text-only :( ]

The solution, as Robert suggested was

      # grub-install /dev/sdb

Thanks a lot :)

Richard Gomes
http://rgomes.info
http://www.linkedin.com/in/rgomes
mobile: +44(77)9955-6813
inum <http://www.inum.net/>: +883(5100)0800-9804
sip:rgomes@ippi.fr

On 31/01/14 09:52, Wilson Jonathan wrote:

On Thu, 2014-01-30 at 21:08 +0000, Richard Gomes wrote:

quoted

[ 3rd time I'm trying to post this! :(  This Majordomo sucks :( ]

Hello,

I have /dev/sda and /dev/sdb in RAID1.

I've discovered that I can boot from partition /dev/sda1 but not from
/dev/sdb1.

Apparently, both disks have equivalent partition tables:

    # sfdisk -l /dev/sda

    Disk /dev/sda: 121601 cylinders, 255 heads, 63 sectors/track
    Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting
    from 0

       Device Boot Start     End   #cyls    #blocks   Id  System
    /dev/sda1   *      0+     60-     61-    487424   fd  Linux raid
    autodetect
    /dev/sda2         60+   7841-   7781-  62499840   fd  Linux raid
    autodetect
    /dev/sda3       7841+ 121601- 113760- 913773568   fd  Linux raid
    autodetect
    /dev/sda4          0       -       0          0    0  Empty


    # sfdisk -l /dev/sdb

    Disk /dev/sdb: 121601 cylinders, 255 heads, 63 sectors/track
    Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting
    from 0

       Device Boot Start     End   #cyls    #blocks   Id  System
    /dev/sdb1   *      0+     60-     61-    487424   fd  Linux raid
    autodetect
    /dev/sdb2         60+   7841-   7781-  62499840   fd  Linux raid
    autodetect
    /dev/sdb3       7841+ 121601- 113760- 913773568   fd  Linux raid
    autodetect
    /dev/sdb4          0       -       0          0    0  Empty



But /parted/ tells me a different story.
This is the culprit: /dev/sdb1 is not known as ext4, as it should be.

    # parted -l
    Model: ATA ST1000DM003-9YN1 (scsi)
    Disk /dev/sda: 1000GB
    Sector size (logical/physical): 512B/4096B
    Partition Table: msdos

    Number  Start   End     Size    Type     File system  Flags
     1      1049kB  500MB   499MB   primary  ext4         boot, raid
     2      500MB   64.5GB  64.0GB  primary               raid
     3      64.5GB  1000GB  936GB   primary               raid


    Model: ATA ST1000DM003-9YN1 (scsi)
    Disk /dev/sdb: 1000GB
    Sector size (logical/physical): 512B/4096B
    Partition Table: msdos

    Number  Start   End     Size    Type     File system  Flags
     1      1049kB  500MB   499MB   primary               boot, raid
     2      500MB   64.5GB  64.0GB  primary               raid
     3      64.5GB  1000GB  936GB   primary               raid

As far as I know, the flags are redundant to a degree; although they
"may" be used as a hint.

Making a drive bootable requires a boot sector loader of some form (as
mentioned in Roberts post).

If you can output the result of  cat /proc/mdstat and also the mdadm
outputs as suggested by Robert then a more informed response can be
given.

quoted

What would be a recommended way to fix this issue?

Thanks