Re: [linux-lvm] Multipath without round-robin?

[Mike Christie <mikenc@us.ibm.com>]

Jedi/Sector One wrote:
>   Hello.
>   
>   I'm trying to get multipath working with LVM2 (2.6.7-rc2-udm2 kernel) with
> an LSI storage array.
> 
>   The array has two FC controllers, HBAs are two identical Qlogic 2340.
>   
>   On the array, "preferred" controllers are assigned to each LUN.
>   
>   Unfortunately, it looks like dm-multipath always does round-robin load
> balancing.

path0 in group0, path1 in group1 etc. When path0 fails you use path1. 
Are you using multipath-tools or settiing up the table by hand. For 
mp-tools there is a failover setting. You still cannot so explciit 
failover but that is in the works.

>   The result is that the array fills up the (SANtricity) error log with
> messages like "LUN was accessed through the wrong controller".
> 
>   Is there any way to keep failover abilities without load balancing?
>   
>   Best regards,
>   
>        -Frank.
>