Re: multipath - AAArgh! How do I turn "features=1 queue_if_no_path" off?

[Hannes Reinecke <hare@suse.de>]

malahal@us.ibm.com wrote:
> John Hughes [john@Calva.COM] wrote:
>> I want to turn queue_if_no_path off and use
>>
>>                polling_interval        5
>>                no_path_retry           5
>>
>> because I've had problems with things hanging when a lun "vanishes" (I 
>> deleted it from my external raid box).
>>
>> But whatever I put in /etc/multipath.conf when I do a "multipath -l" or 
>> "multipath-ll" it shows:
> 
> Did you reload the mapper table?
> 
>> 360024e80005b3add000001b64ab05c87dm-28 DELL    ,MD3000        
>> [size=68G][features=1 queue_if_no_path][hwhandler=1 rdac]
>> \_ round-robin 0 [prio=3][active]
>> \_ 3:0:1:13 sdad 65:208 [active][ready]
>> \_ round-robin 0 [prio=0][enabled]
>> \_ 4:0:0:13 sdas 66:192 [active][ghost]
>>
Which is entirely correct. The 'queue_if_no_path' flag _has_ to
be set here as we do want to retry failed paths, if only for
a limited amount of retries.

The in-kernel dm-multipath module should handle the situation correctly
and switch off the queue_if_no_path flag (= pass I/O errors upwards)
when the amount of retries is exhausted.

You can only switch the flag off by setting 'no_path_retry failed'.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
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