[dm-devel] RE: regarding DM device for a single path.

[christophe varoqui]

> 
>      1. I tested your latest user space tools with 2.6.9-11.41 kernel.
>         Used the default created devices for multipathing. The path
>         status is getting updated appropriately for HSV200 arrays.
>          However the failback functionality is not working for me. I
>         have configure value for “failback” variable
>         in /etc/multipath.conf as zero for immediate failback, but
>         when the failed path in the original path group comes back
>         online, the IO is not failed back the old pathgroup.
> 
I'll look into that when I return from vacation in 2 weeks.
I think I'll have the appropriate HW at hand.
 
> 
>      1. In yesterday’s discussion, you mentioned that DM device nodes
>         will not be created for the physical devices which are having
>         single path.  Assuming one particular device had 2 paths and
>         DM device was created and used by the applications. While the
>         system is rebooted for some reasons, and if one of the paths
>         for this device is lost, then the subsequent reboot will not
>         create the DM device as it sees only one path for this device.
>         And the DM device might be created only if the other path
>         comes back online and the HBA driver is rescanned for new
>         devices.  This may not be desired multipathing behaviour, as
>         the DM device does not exist if we one path for the device.
> 
To my knowledge, mono-path multipath map are created.
At least they used to be last time I check with a parallel SCSI server.
Can you back with testing ?

Regards,

-- 
christophe varoqui <christophe.varoqui at free.fr>