[linux-lvm] Question about filter behavior on pvcreate /dev/md0

[Heming Zhao]

Hello Zdenek,

Thank you for your reply. Your method works well.
I also understand the filter rules gradually.


On 6/14/19 4:51 PM, Zdenek Kabelac wrote:
> Dne 13. 06. 19 v 9:41 Heming Zhao napsal(a):
>> Hello List,
>>
>> I created a md device, and used pvcreate to format it.
>> But the pvcreate was failed with filter rules.
>> the filter in /etc/lvm/lvm.conf:
>> ```
>> filter = [ "r|/dev/.*/by-path/.*|", "r|/dev/.*/by-id/.*|",
>> "r|/dev/fd.*|", "r|/dev/cdrom|" ]
>> ```
> 
> 
> Hi
> 
> This filter mostly eliminates ANY block device you have in the system.
> The logic of filtering can be seen as puzzling, but please try to read 
> carefully comments in lvm.conf about filtering. It's explained there in 
> the great detail.
> 
> As soon as the 'accept' rule is seen - the device gets accepted.
> Otherwise if you remove device path - all it's associated clones will be 
> also removed.
> 
> So when you block device generates one of /dev/*/by-path access paths 
> (and I'd assume /dev/md0 should be) - it gets removed.
> 
> As 'quick fix' you can add 'a' rule for /dev/md.*...
> 
> Regards
> 
> Zdenek
>