Howto: implement AMD SB9xx RAID5 support in dmraid

Mark-Willem Jansen markwillem at
Mon Mar 26 12:34:02 UTC 2012

Hi Phillip,

> I would advise using mdadm instead since it is much better supported and 
> more reliable and feature complete.

Won't mdadm overwrite the metadata written to the disk by the BIOS/UEFI.
The RAID needs to be accessible from Windows and Linux. And I already use
the RAID under windows for my USER(would be /home for linux) directory.

> I believe it should just work unless they changed the format of the 
> dmsetup table.

Could be true. Maybe just loading the appropriate module will work.

> dmraid -n doesn't already recognize it?  You can find the existing known 
> offsets in pdc.h.

I will run the command tonight when I am home. But as far as I can tell I
only get "found 0 sectors" for all the three disks. Maybe adding the offset
patch from ubuntu will do the trick. 

> dmraid already understands pdc metadata.

Does this include all the info needed to setup a RAID-5. For instance there
are four different algorithm, left-asymmetric, left-symmetric, right-asymmetric
and right-symmetric that can be picked.

> Ubtunu 12.04 has switched to letting kpartx activate the partitions 
> instead of dmraid, which supports GPT.

Another patch I can apply to the source tree. :-)

Kind regards,


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