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

[Austin Gonyou <austin@coremetrics.com>]

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Austin Gonyou wrote:

> You could just use the qlogic hba driver failover.
>
> ql2xfailover=1 in your rmodules.conf


One caveat, if you're not running with write cache mirroring on you your 
volumes, then no matter md or qla failover, you may get data corruption. 
Some apps don't run well with it on because of the performance hit.

> 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.
>>
>>   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.
>>       
>>


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