Thanks for replying Greg.

>This:
>
>>  The
>>  console output for the SCSI pair at the point of the crash was:
>>
>>  RECON: initiating reconstruction on col 0 -> spare at col 2
>>  sd1(isp0:0:2:0):  Check Condition on CDB: 0x08 00 10 40 80 00
>>       SENSE KEY:  Hardware Error
>>        ASC/ASCQ:  ASC 0x44 ASCQ 0x9d
>>
>>  raid0: IO Error.  Marking /dev/sd1a as failed.
>>  raid0: Recon read failed!
>
>and:
>
>>  and for the IDE pair:
>>
>>  Aug 19 17:11:41 www /netbsd: stray isa irq 14
>>  Warning: truncating spare disk /dev/wd0a to 4127616 blocks
>>  Aug 19 17:12:50 www su: ray to root on /dev/ttyp1
>>  RECON: initiating reconstruction on col 0 -> spare at col 2
>>  wd1a: error reading fsbn 1031488 of 1031488-1031615 (wd1 bn 1031488;
>>  cn 1023 tng
>>  wd1: (uncorrectable data error)
>[snip]
>>
>>  raid0: IO Error.  Marking /dev/wd1a as failed.
>>  raid0: Recon read failed!
>
>indicate hardware errors,

Yes, I'm afraid I was wasting your time with my query.  :(

>and right now the reconstruction code in RAIDframe doesn't deal at 
>all with those sorts of errors.

OK, that's worth knowing.  :)

I tried again to make a RAID-1 bootable array using the IDE pair of 
disks I mentioned, this time in a PC.  I sat in front of the console 
when I issued the `raidctl -F component0 raid0' command and observed 
the failure occur.  It certainly happened in the vicinity of the bad 
sectors, so they must have been the cause.  So, it seems a sector by 
sector copy is done of the whole RAID partition during the 
reconstruction process, regardless of what kinds of partitions are 
within it?

There was something strange about the SCSI pair too but I can't 
explain it.  I swapped the SCSI ID's of the two disks and plugged 
each into the other's connector, tried the process again, and it 
worked beautifully.  Hot-removing one, formatting it under DOS, 
plugging it back into the Alpha, and adding it back into the array 
went smoothly too, just as you'd hope it would.

>Was the parity of the sets "clean" when you started the reconstruct? )

No, the parity was dirty, and I couldn't see how to make it clean 
before adding the second RAID partition to the array.  Is it possible 
to do that?


Ray