[linux-lvm] LVM cachepool inconsistency after power event

[Zdenek Kabelac]

Dne 05. 10. 21 v 13:34 Krzysztof Chojnowski napsal(a):
> On Tue, Oct 5, 2021 at 06:35 AM Ming-Hung Tsai <mingnus at gmail.com> wrote:
>> Could you help run cache_check independently, to see the error messages? Thanks.
>>
>> # sudo lvchange -ay -f vg0/wdata_cachepool_cpool_cmeta
>> # sudo cache_check /dev/mapper/vg0-wdata_cachepool_cpool_cmeta
>> # sudo lvchange -an -f vg0/wdata_cachepool_cpool_cmeta
> 
> Thanks for your help, this is what I get:
> $ sudo lvchange -ay -f vg0/wdata_cachepool_cpool_cmeta
> Do you want to activate component LV in read-only mode? [y/n]: y
>    Allowing activation of component LV.
> $ sudo cache_check /dev/mapper/vg0-wdata_cachepool_cpool_cmeta
> examining superblock
> examining mapping array
>    missing mappings [1, 0]:
>      missing blocks
> examining hint array
>    missing mappings [1, 0]:
>      missing blocks
> examining discard bitset
> $ echo $?
> 1
> $ sudo lvchange -an -f vg0/wdata_cachepool_cpool_cmeta
> $ sudo lvchange -ay   vg0/tpg1-wdata
>    Check of pool vg0/wdata_cachepool_cpool failed (status:1). Manual
> repair required!

Hello Krzystof

You need to repair your cache-pool metadata.

But before continuing with advices - what is the version of kernel lvm2 & your
device-mapper-persistent-data package (aka  'cache_check -V)

Component activation allows activation of your _cmeta LV - but only in 
read-only mode - so repair must go into a new LV.

Since cache_check reported  '1' exist code (as an error) - your metadata do 
require a fix.

lvconvert --repair should be able to handle this case - although likely 
without 'smart' placement' of fixed metadata (pvmove needed after metadata fix)

You can allocated your new metadata and easily cache_repair them.


Regards

Zdenek