Checking support levels

Daniel O'Connor darius at
Sun May 18 06:09:31 UTC 2008

On Fri, 16 May 2008, Jonathan wrote:
> To confirm the RAID1 matters because RAID 10 is RAID 0 (stripe) over
> RAID 1 (mirrors)?
> I don't mind having to revert to BIOS for rebuild in the event of a
> hd fault, but I wouldn't mind understanding a little more about the
> lack of error handling.
> Do you mean if one disk in the underlying mirror set fails that
> dmraid will 1) ignore and not notify
> 2) fall over in a big heap
> 3) notify, keep running but not rebuild
> 4) not handle inconsistencies without reversion to BIOS?

Read doc/dmraid_design.txt - dmraid can't update the RAID metadata to 
record a disk failure.

I am not sure what happens in the event of a disk failure - up to 
devmapper I guess.

I would say that if you had a degraded array and rebooted the BIOS 
wouldn't know it's degraded and DM wouldn't either, so you might fail 
to boot, boot but get corrupted data, etc etc..

Daniel O'Connor software and network engineer
for Genesis Software -
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C
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