[linux-lvm] How to convert a single path to a multipath after using dm-multipath

[David Teigland]

On Tue, Apr 11, 2023 at 01:29:42PM +0800, Zhiyong Ye wrote:
> and lv on it. I then turn on the multipath function and merge the two paths
> into a new device (/dev/mapper/matha), and I get the following error when I
> execute the lvm command.
> 
> # pvs
> WARNING: Not using device /dev/mapper/matha for PV
> HgL3xR-qTio-m75Q-nGAO-Un0U-8uHk-wHbH25.
> WARNING: PV HgL3xR-qTio-m75Q-nGAO-Un0U-8uHk-wHbH25 prefers device /dev/sda
> because device is used by LV.
> PV           VG                      Fmt  Attr PSize  PFree
> /dev/sda     is-he57e6mr4wemb19kgf8i lvm2 a--  10.00t 9.98t

> May you please advise how one can convert the pv used by vg from sda to
> matha without affecting the current lv usage.

lvchange --refresh should refresh the active LV to use mpatha.  To avoid
this, you might configure mpath on sda alone prior to adding the second
path.

Dave