ISCSI and multipath

[Sossi Andrej]

Gary Palmer wrote:
> On Fri, Jan 09, 2009 at 12:03:26PM +1100, Andrew Snow wrote:
>   
>> Sossi Andrej wrote:
>>     
>>> Another question about MD3000i.
>>> My MD3000i have 2 controller and every controller have 2 net interface.
>>> My FreeBSD server is connect on NAS server with 2 network cards throw 
>>> out 2 switch on th 2 networks. (192.168.253.X and 192.168.252.X).
>>> In the official manual is written if the primary controller (or net) 
>>> have a problem the NAS automatically switch disks drive on second 
>>> controller. For this is required MPIO on Windows or MPP on Linux. It is 
>>> supported also on FreeBSD?
>>>       
>> If you only wanted to do failover at the network level with shared IP 
>> address, you could use lagg.
>>
>> However, since you have different IP subnets for each network, you 
>> probably want to look at using geom_fox.  You set up two iSCSI 
>> connections, one to each controller, and geom_fox on top to make it 
>> appear as a single disk device.
>>     
>
> FreeBSD 7.0 and later also has geom_multipath, which I've been
> told (no experience) is a better approach.  I suggest you 
> review documentation for both and make your own decision
>
> Regards,
>
> Gary
>   
I read geom_fox an geom_mirror man pages. I think the geom_mirror is 
best way, but not everything is clear for me.
This is scenario:

NAS server:
controller 0 interface 0: 192.168.253.254
controller 1 interface 0: 192.168.253.253
controller 0 interface 1: 192.168.252.254
controller 1 interface 1: 192.168.252.253

FreeBSD:
re0: 192.168.253.1
re1: 192.168.252.1

FreeBSD is connected through 2 switches, one for net 192.168.253.X and 
one for 192.168.252.X. In the iscsi.conf file my target is 192.168.253.254.

ISCSI initiator creates only one device for disk. If I will use 
geom_multipath, I must launch initiator 2 times (or 4 times), each for 
one interface. Then I must configure geom_multipart device for /dev/da0 
, /dev/da5, ... Is this correct? If yes, I plan some tests and then I 
will write the results.

Thanks

-- 
Sossi Andrej
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