Bug#641584: mdadm-raid does not assemble mds on multipath devices

[Michael Tokarev]

On 14.09.2011 18:16, martin f krafft wrote:
>> Since mdadm and multipath-tools do not depend on each other in
>> their init.d LSB headers, insserv sorts mdadm-raid before
>> multipath-tools-boot. This prevents the assembly of MDs on
>> multipath devices.
> 
> I do not have experience with multipath, hence my question:
> I understand you want to assemble MDs on multipath devices. Is this
> the only sensible stacking? Or is it plausible to have multipath
> devices on MDs?

Yes this is the only sensible stacking - component devices on
multipath, md on top of it.  So it is the right fix too -- to
have another init order dependency on multipath-tools-boot.

> mdadm can also handle multipath devices. Is this the same thing?

No it is not.  md amd dm subsystem has several common components.
This is dm multipath - the one which is actually used, with good
tools written for it.  mdadm is not there yet, and it is not
widely used for this purpose.

/mjt