DRAFT - Remote Conversion to Linux Software RAID-1 for Crazy Sysadmins HOWTO

[Warren Togami]

Alexandre Oliva wrote:
> On Feb 22, 2004, Warren Togami <warren at togami.com> wrote:
> 
> 
>>Any suggestions for improving the procedure
> 
> 
> Don't convert the first disk's partition types to raid before you
> actually make them raid members.  Should they happen to contain raid
> control blocks, for any reason (such as having been raid members
> before) this might prevent the newly-created raid devices from being
> started.  Yes, this has happened to me in the past :-)
> 
> Create the raid devices with `missing /dev/hdc?', instead of the other
> way round, such that /dev/hda? is the master copy.  This is
> particularly important for the boot partition.  Should the boot
> partition happen to need a resync due to a crash, you'll be
> overwriting the GRUB boot info in /dev/hda with that in /dev/hdc.
> This may be bad, and leave you with a non-rebootable system.  Yes,
> this has happened to me in the past :-)
> 

Hmm, if I have a running system made this way now, is there anything I 
can do to switch the master copy?

Thank you for the suggestions!

> 
>>mdadm manual start on RHEL3 failed would be appreciated.
> 
> 
> I wouldn't be surprised if the reason for the mdadm failure turns out
> to be https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=107988
> 

Bingo, that seems to describe the behavior.

Warren Togami
wtogami at redhat.com