Re: How to convert a single path to a multipath after using dm-multipath

Zhiyong Ye <[email protected]>
Newsgroups gmane.linux.lvm.general
Message-ID <[email protected]>
Hi Giorgio,

Thank you for your reply and detailed answers.

When I filtered out the sda device on the lvm configuration file it 
works fine.

Thank you again for your help.

Regards

Zhiyong

On 4/13/23 6:54 PM, Giorgio Bersano wrote:
> Hi Zhiyong,
> did you filter out the device in lvm.conf ?
> 
> filter = [ ... , "r/sd.*/" , ... ]
> 
>           or  "r/sda/" if you want to only exclude  sda
> 
> Regards,
> Giorgio.
> 
> 
> Il giorno gio 13 apr 2023 alle ore 08:55 Zhiyong Ye 
> <[email protected] <mailto:[email protected]>> ha scritto:
> 
> 
>     Hi Dave,
> 
>     Thank you for your reply.
> 
>     Because I had not considered multi-pathing before, there is no way to
>     configure mpath on sda alone on the current stock of machines. And I
>     tested this in my environment using lvchange --refresh, but it doesn't
>     switch the active LV to use mpatha.
> 
>     # lvchange --refresh is-he57e6mr4wemb19kgf8i
>     WARNING: Not using device /dev/mapper/mpatha 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.
> 
>     # pvs
>     WARNING: Not using device /dev/mapper/mpatha 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
> 
>     This is because duplicate PVs are encountered during the disk discovery
>     phase, but lvmcache tends to use sda because it is currently being used
>     by LV and mpatha will be dropped.
> 
>     I debugged the _choose_duplicates function in lvmcache and printed the
>     following log:
>     lvm[3352450]: PV HgL3xRqTiom75QnGAOUn0U8uHkwHbH25 compare duplicates:
>     /dev/mapper/mpatha 254:3. /dev/sda 8:16. device_hint /dev/sda.
>     vm[3352450]: PV HgL3xRqTiom75QnGAOUn0U8uHkwHbH25: size 21474836480.
>     /dev/mapper/mpatha is 21474836480. /dev/sda is 21474836480.
>     lvm[3352450]: PV HgL3xRqTiom75QnGAOUn0U8uHkwHbH25: /dev/mapper/mpatha
>     was prev <none>. /dev/sda was prev <none>.
>     lvm[3352450]: PV HgL3xRqTiom75QnGAOUn0U8uHkwHbH25:
>     /dev/mapper/mpatha is
>     in subsystem. /dev/sda is not in subsystem.
>     lvm[3352450]: PV HgL3xRqTiom75QnGAOUn0U8uHkwHbH25:
>     /dev/mapper/mpatha is
>     dm. /dev/sda is not dm.
>     lvm[3352450]: PV HgL3xRqTiom75QnGAOUn0U8uHkwHbH25: /dev/mapper/mpatha
>     has no mounted fs. /dev/sda has no mounted fs.
>     lvm[3352450]: PV HgL3xRqTiom75QnGAOUn0U8uHkwHbH25:
>     /dev/mapper/mpatha is
>     not used for LV. /dev/sda is used for LV.
>     lvm[3352450]: PV HgL3xRqTiom75QnGAOUn0U8uHkwHbH25 with duplicates will
>     change from /dev/mapper/mpatha to /dev/sda.
>     lvm[3352450]: Dropping unchosen duplicate /dev/mapper/mpatha
>     lvm[3352450]: Adding chosen duplicate /dev/sda
> 
>     Is there any way to change the PV preference policy in
>     _choose_duplicates?
> 
> 
> 
> 
>     Regards
> 
>     Zhiyong
> 
>     On 4/11/23 9:31 PM, David Teigland wrote:
>      > 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
>      >
> 
>     _______________________________________________
>     linux-lvm mailing list
>     [email protected] <mailto:[email protected]>
>     https://listman.redhat.com/mailman/listinfo/linux-lvm
>     <https://listman.redhat.com/mailman/listinfo/linux-lvm>
>     read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>     <http://tldp.org/HOWTO/LVM-HOWTO/>
> 

_______________________________________________
linux-lvm mailing list
[email protected]
https://listman.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
lmpx.com only provides a reader for public news (NNTP) servers. It is not affiliated with the servers or forums shown here and is not responsible for the content of articles, which is written by their respective authors.