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
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