[linux-lvm] About online pvmove/lvresize on shared VG

[Gang He]

Hi David,

Thank for your reply.
more questions,

On 7/9/2020 12:05 AM, David Teigland wrote:
> On Wed, Jul 08, 2020 at 03:55:55AM +0000, Gang He wrote:
>> but I cannot do online LV reduce from one node,
>> the workaround is to switch VG activation_mode to exclusive, run lvreduce command on the node where VG is activated.
>> Does this behaviour is by-design? or a bug?
> 
> It was intentional since shrinking the cluster fs and LV isn't very common
> (not supported for gfs2).
OK, thank for confirmation.

> 
>> For pvmove command, I cannot do online pvmove from one node,
>> The workaround is to switch VG activation_mode to exclusive, run pvmove command on the node where VG is activated.
>> Does this behaviour is by-design? do we do some enhancements in the furture?
>> or any workaround to run pvmove under shared  activation_mode? e.g. --lockopt option can help this situation?
> 
> pvmove is implemented with mirroring, so that mirroring would need to be
> replaced with something that works with concurrent access, e.g. cluster md
> raid1.  I suspect there are better approaches than pvmove to solve the
> broader problem.
Sorry, I am a little confused.
In the future, we can do online pvmove when VG is activated in shared 
mode? from man page, I feel these limitations are temporary (or Not Yet 
Complete).
By the way, --lockopt option can help this situation? I cannot find the 
detailed description for this option in manpage.

Thanks
Gang

> 
> Dave
>