Asymmetric logical unit access(ALUA) and FreeBSD

[Matthew Jacob]

On 3/26/2010 1:27 AM, Omer Faruk Sen wrote:
> I want to know if FreeBSD supports Asymmetric logical unit access ?
>    
Not as such, no. The only multipath really is at the GEOM layer, which 
is dead stupid.

It should be ALUA aware, but I'll rate it lower than getting the FreeBSD 
probe code to use REPORT LUNS.

>
> > From http://www.vicengle.org/san/dmp.php
>
> ALUA, Asymmetric logical unit access
>
> ALUA is a relatively new multipathing technology for asymmetrical
> arrays. If the array is ALUA compliant and the host multipathing layer
> is ALUA aware then virtually no additional configuration is required
> for proper path management by the host. An Asymmetrical array is one
> which provides different levels of access per port. For example on a
> typical Asymmetrical array with 2 controllers it may be that a
> particular LUN's paths to controller-0 port-0 are active and optimized
> while that LUN's paths to controller-1 port-0 are active
> non-optimized. The multipathing layer should then use paths to
> controller-0 port-0 as the primary paths and paths to controller-1
> port-0 as the secondary (failover) paths. Sun Solaris 10 MPxIO is an
> example of an ALUA aware multipathing solution. A Netapp FAS3020 with
> Data ONTAP 7.2.x is an example of an ALUA compliant array.
>
>
>
> Regards.
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