[DRBD-user] Found a new disk flush error code

[Thomas Reinhold]

Hi,

I've done a little further testing and ran DRBD directly on top of the  
raid set (without using dm_crypt). Still got the same disk flush  
errors when having flushing enabled.

So can I assume that either the lower level scsi driver megaraid_sas  
(Debian 2.6.18.6-amd64) or the raid controller (LSI MegaRaid 1078)  
does not support flushing?


And another question: Can disabling flushing in DRBD cause any other  
problems than data corruptions at power loss?


Am 15.12.2008 um 16:45 schrieb Thomas Reinhold:

>
> Thanks again. The driver module is sas_megaraid (I'm using Debian  
> 2.6.18 dm-crypt, not RedHat).
>
>
> Am 15.12.2008 um 15:35 schrieb Lars Ellenberg:
>> On Mon, Dec 15, 2008 at 03:14:28PM +0100, Thomas Reinhold wrote:
>>> Thanks for your quick answer.
>>>
>>> This is the complete error message (I shoud have posted that in  
>>> the first
>>> place, sorry):
>>>
>>>
>>>    Dec 11 21:47:56 bftest-54 kernel: FAILED
>>>    Dec 11 21:47:56 bftest-54 kernel:   status = 1, message = 00,  
>>> host = 0, driver = 08
>>>    Dec 11 21:47:56 bftest-54 kernel:   <6>sd: Current: sense key:  
>>> Illegal Request
>>>    Dec 11 21:47:56 bftest-54 kernel:     Additional sense: Invalid  
>>> command operation code
>>
>> well, that is from the scsi layer.
>> and yes, that is exactly the decoded scsi_execute_req return value
>> 0x8000002 ;)
>>
>>>    Dec 11 21:47:56 bftest-54 kernel: drbd0: local disk flush  
>>> failed with
>>>    status 134217730
>>>
>>> What I forgot to mention is that DRBD runs on top of a dm device  
>>> (dm-crypt),
>>> which in turn runs on top of the raid array. Could that cause the  
>>> problem?
>>
>> I was not aware that redhat has patched its 2.6.18 dm-crypt to
>> (pretend to?) support flushed/barriers.
>>
>> but that should be irrelevant in this context.
>>
>> apparendly your lower level driver (what driver module is in use?)  
>> does
>> not support flush requests, or something in the device mapper stack
>> converts the flush request into something that the driver does not
>> understand.
>>
>> we may consider to handle any return value != 0 in the same way in  
>> drbd.
>> meanwhile, the correct fix is:
>>
>>>        I have disabled disk flushing for now, and the error  
>>> obiously has gone.
>>
>> -- 
>> : Lars Ellenberg
>> : LINBIT | Your Way to High Availability
>> : DRBD/HA support and consulting http://www.linbit.com
>>
>> DRBD® and LINBIT® are registered trademarks of LINBIT, Austria.
>> __
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