[dm-devel] [PATCHv5 00/14] dm-zoned: metadata version 2

[Hannes Reinecke]

On 5/11/20 12:55 PM, Damien Le Moal wrote:
> On 2020/05/11 11:46, Damien Le Moal wrote:
>> Mike,
>>
>> I am still seeing the warning:
>>
>> [ 1827.839756] device-mapper: table: 253:1: adding target device sdj caused an
>> alignment inconsistency: physical_block_size=4096, logical_block_size=4096,
>> alignment_offset=0, start=0
>> [ 1827.856738] device-mapper: table: 253:1: adding target device sdj caused an
>> alignment inconsistency: physical_block_size=4096, logical_block_size=4096,
>> alignment_offset=0, start=0
>> [ 1827.874031] device-mapper: table: 253:1: adding target device sdj caused an
>> alignment inconsistency: physical_block_size=4096, logical_block_size=4096,
>> alignment_offset=0, start=0
>> [ 1827.891086] device-mapper: table: 253:1: adding target device sdj caused an
>> alignment inconsistency: physical_block_size=4096, logical_block_size=4096,
>> alignment_offset=0, start=0
>>
>> when mixing 512B sector and 4KB sector devices. Investigating now.
> 
> 
> OK. Figured that one out: the 500GB SSD I am using for the regular device is
> 976773168 512B sectors capacity, that is, not a multiple of the 256MB zone size,
> and not even a multiple of 4K. This causes the creation of a 12MB runt zone of
> 24624 sectors, which is ignored. But the start sector of the second device in
> the dm-table remains 976773168, so not aligned on 4K. This causes
> bdev_stack_limits to return an error and the above messages to be printed.
> 
> So I think we need to completely ignore the eventual "runt" zone of the regular
> device so that everything aligns correctly. This will need changes in both
> dmzadm and dm-zoned.
> 
> Hannes, I can hack something on top of your series. Or can you resend with that
> fixed ?
> 
> 
I _thought_ I had this fixed; the idea was to manipulate the 'runt' zone 
such that the zone would always displayed as a zone with same size as 
all the other zones, but marked as offline. IE the (logical) zone layout 
would always be equidistant, with no runt zones in between.
 From that perspective the actual size of the runt zone wouldn't matter 
at all.

Lemme check.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke            Teamlead Storage & Networking
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