system boot _sometimes_ fails after `root on raid0a dumps on raid0b'

[Jukka Salmi <j+nbsd%2009.salmi.ch@localhost>]

Hello,

[Until recently the system in question was running -current (5.99.14)
 and also showed the same problem; that's why I Cc'ed current-users@]

I'm seeing this on a NetBSD/i386 5.0_STABLE system which has its root
file system on a RAID 1 set: every now and then (about once in five or
ten times) the system boots fine until printing

        [...]
        raid0: RAID Level 1
        raid0: Components: /dev/wd0a /dev/wd1a
        raid0: Total Sectors: 16777216 (8192 MB)
        boot device: raid0
        root on raid0a dumps on raid0b

and then stops (or at least stops outputting console messages).  But
most of the time the system boots just fine:

        [...]
        root on raid0a dumps on raid0b
        root file system type: ffs
        [...]

Anybody seeing the same?  Is there anything I can do in ddb to find out
what went wrong at that point?


Regards, Jukka

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