[linux-lvm] lvconvert -m 0 /dev/varlin/distfiles /dev/md0 => zero filled logical volume

[Raimonds Cicans]

Hello.

I am trying to move LVM setup from old RAID md0 to new RAID md1

I did "lvconvert -m 1 /dev/path/to/logical_volume /dev/md1" on bunch of
logical volumes.
Everything went without problems.

Then I tried to remove md0 from one of logical volumes by running command:
lvconvert -m 0 /dev/varlin/distfiles /dev/md0

I tried to mount this logical volume, but failed.

Then I checked first megabyte of logical volume it was zero filled.

Partial output of "lvs -o+devices":
LV VG Attr LSize Pool Origin Data% Meta%
Move Log Cpy%Sync Convert Devices

backup varlin -wi-ao---- 100,00g
/dev/md0(6304)

backup varlin -wi-ao---- 100,00g
/dev/md0(8544)

data varlin -wi-ao---- 20,00g
/dev/md0(28384)

distfiles varlin -wi-a----- 20,00g
/dev/md1(2738)

ftp varlin rwi-aor--- 10,00g
100,00 ftp_rimage_0(0),ftp_rimage_1(0)

ftpdown varlin rwi-aor--- 10,00g
100,00 ftpdown_rimage_0(0),ftpdown_rimage_1(0)



lvm2: 2.02.116
kernel: 4.4.2


Questions:

1) What I did wrong?
2) Is it possible to salvage /dev/varlin/distfiles or I must restore it
from backups?
3) What I should do now to get system to safe state?


Best regards,
Raimonds Cicans

[Stuart Gathman]

Post by Raimonds Cicans
Hello.
I am trying to move LVM setup from old RAID md0 to new RAID md1
I did "lvconvert -m 1 /dev/path/to/logical_volume /dev/md1" on bunch
of logical volumes.
Everything went without problems.
lvconvert -m 0 /dev/varlin/distfiles /dev/md0
I tried to mount this logical volume, but failed.
Then I checked first megabyte of logical volume it was zero filled.
LV VG Attr LSize Pool Origin Data% Meta%
Move Log Cpy%Sync Convert Devices
backup varlin -wi-ao---- 100,00g
/dev/md0(6304)
backup varlin -wi-ao---- 100,00g
/dev/md0(8544)
data varlin -wi-ao---- 20,00g
/dev/md0(28384)
distfiles varlin -wi-a----- 20,00g
/dev/md1(2738)
ftp varlin rwi-aor--- 10,00g 100,00
ftp_rimage_0(0),ftp_rimage_1(0)
ftpdown varlin rwi-aor--- 10,00g 100,00
ftpdown_rimage_0(0),ftpdown_rimage_1(0)
lvm2: 2.02.116
kernel: 4.4.2
1) What I did wrong?

I would have used pvmove. Using lvconvert, I think you needed to sync
the mirrors before removing a leg.

Post by Raimonds Cicans
2) Is it possible to salvage /dev/varlin/distfiles or I must restore
it from backups?

Use the metdata backups (/etc/lvm) to restore lvm to before you removed md0.

Post by Raimonds Cicans
3) What I should do now to get system to safe state?

The system is probably fine - you just removed you data.

[Raimonds Cicans]

Post by Stuart Gathman

Post by Raimonds Cicans
I am trying to move LVM setup from old RAID md0 to new RAID md1
I did "lvconvert -m 1 /dev/path/to/logical_volume /dev/md1" on bunch
of logical volumes.
Everything went without problems.
lvconvert -m 0 /dev/varlin/distfiles /dev/md0
I tried to mount this logical volume, but failed.
Then I checked first megabyte of logical volume it was zero filled.
LV VG Attr LSize Pool Origin Data% Meta%
Move Log Cpy%Sync Convert Devices
backup varlin -wi-ao---- 100,00g /dev/md0(6304)
backup varlin -wi-ao---- 100,00g /dev/md0(8544)
data varlin -wi-ao---- 20,00g /dev/md0(28384)
distfiles varlin -wi-a----- 20,00g /dev/md1(2738)
ftp varlin rwi-aor--- 10,00g 100,00
ftp_rimage_0(0),ftp_rimage_1(0)
ftpdown varlin rwi-aor--- 10,00g 100,00
ftpdown_rimage_0(0),ftpdown_rimage_1(0)
lvm2: 2.02.116
kernel: 4.4.2
1) What I did wrong?

I would have used pvmove. Using lvconvert, I think you needed to sync
the mirrors before removing a leg.

How do I sync mirror before removing leg? I thought 100 in Cpy%Sync
column mean - everything is in sync.


Best regards,
Raimonds Cicans

[Raimonds Cicans]

Post by Raimonds Cicans
I am trying to move LVM setup from old RAID md0 to new RAID md1
I did "lvconvert -m 1 /dev/path/to/logical_volume /dev/md1" on bunch of
logical volumes.
Everything went without problems.
lvconvert -m 0 /dev/varlin/distfiles /dev/md0
I tried to mount this logical volume, but failed.
Then I checked first megabyte of logical volume it was zero filled.
LV VG Attr LSize Pool Origin Data% Meta%
Move Log Cpy%Sync Convert Devices
backup varlin -wi-ao---- 100,00g
/dev/md0(6304)
backup varlin -wi-ao---- 100,00g
/dev/md0(8544)
data varlin -wi-ao---- 20,00g
/dev/md0(28384)
distfiles varlin -wi-a----- 20,00g
/dev/md1(2738)
ftp varlin rwi-aor--- 10,00g 100,00
ftp_rimage_0(0),ftp_rimage_1(0)
ftpdown varlin rwi-aor--- 10,00g 100,00
ftpdown_rimage_0(0),ftpdown_rimage_1(0)
lvm2: 2.02.116
kernel: 4.4.2

I made following test:
I unmounted /opt and dumped to files following volumes:
/dev/mapper/varlin-opt
/dev/mapper/varlin-opt_rimage_0
/dev/mapper/varlin-opt_rimage_1

and then diff-ed them.

/dev/mapper/varlin-opt_rimage_0 was not equal with /dev/mapper/varlin-opt.
Why??? I thought 100 in Cpy%Sync column of lvs output mean volume is
fully synchronized.

With "lvconvert -m0" I removed /dev/mapper/varlin-opt_rimage_0 from
/dev/mapper/varlin-opt.

I did some test of volume - everything was normal.

My plan for now:
for each mirrored volume:
1) do volume content backup
2) umount volume
3) run md5sum for volume itself and all mirror sub-volumes
4) with "lvconvert -m0" remove sub-volume which is not equal to volume
5) do some volume tests
6) if something went wrong - restore volume content from backup
7) if on step 4 was removed new RAID md1, then make pvmove to md1


Best regards,
Raimonds Cicans

[Raimonds Cicans]

Post by Raimonds Cicans

Post by Raimonds Cicans
I am trying to move LVM setup from old RAID md0 to new RAID md1
I did "lvconvert -m 1 /dev/path/to/logical_volume /dev/md1" on bunch of
logical volumes.
Everything went without problems.
lvconvert -m 0 /dev/varlin/distfiles /dev/md0
I tried to mount this logical volume, but failed.
Then I checked first megabyte of logical volume it was zero filled.
LV VG Attr LSize Pool Origin Data% Meta%
Move Log Cpy%Sync Convert Devices
backup varlin -wi-ao---- 100,00g
/dev/md0(6304)
backup varlin -wi-ao---- 100,00g
/dev/md0(8544)
data varlin -wi-ao---- 20,00g
/dev/md0(28384)
distfiles varlin -wi-a----- 20,00g
/dev/md1(2738)
ftp varlin rwi-aor--- 10,00g 100,00
ftp_rimage_0(0),ftp_rimage_1(0)
ftpdown varlin rwi-aor--- 10,00g 100,00
ftpdown_rimage_0(0),ftpdown_rimage_1(0)
lvm2: 2.02.116
kernel: 4.4.2

/dev/mapper/varlin-opt
/dev/mapper/varlin-opt_rimage_0
/dev/mapper/varlin-opt_rimage_1
and then diff-ed them.
/dev/mapper/varlin-opt_rimage_0 was not equal with /dev/mapper/varlin-opt.
Why??? I thought 100 in Cpy%Sync column of lvs output mean volume is
fully synchronized.
With "lvconvert -m0" I removed /dev/mapper/varlin-opt_rimage_0 from
/dev/mapper/varlin-opt.
I did some test of volume - everything was normal.
1) do volume content backup
2) umount volume
3) run md5sum for volume itself and all mirror sub-volumes
4) with "lvconvert -m0" remove sub-volume which is not equal to volume
5) do some volume tests
6) if something went wrong - restore volume content from backup
7) if on step 4 was removed new RAID md1, then make pvmove to md1

Plan failed, because one of sata controllers failed.
I moved all disks to other computer and booted from SystemRescueCD.
All volumes was synced. I checked by md5sum-ing volumes itself an both
their legs.
Then I without problems moved all remaining volumes to new RAID.

So, case is closed.

Best regards,
Raimonds Cicans

[Heinz Mauelshagen]

Post by Raimonds Cicans
Hello.
I am trying to move LVM setup from old RAID md0 to new RAID md1
I did "lvconvert -m 1 /dev/path/to/logical_volume /dev/md1" on bunch
of logical volumes.
Everything went without problems.
lvconvert -m 0 /dev/varlin/distfiles /dev/md0
I tried to mount this logical volume, but failed.

Please provide "lvs -a" and the output of the lvconvert commands to tell
better what failed here.

Did you check, that your new 2-legged mirror got convert to/from and
that it synced properly?

That said, this is a valid procedure beside using pvmove.

Can't tell what failed w/o further information.

Heinz

Post by Raimonds Cicans
Then I checked first megabyte of logical volume it was zero filled.
LV VG Attr LSize Pool Origin Data% Meta%
Move Log Cpy%Sync Convert Devices
backup varlin -wi-ao---- 100,00g
/dev/md0(6304)
backup varlin -wi-ao---- 100,00g
/dev/md0(8544)
data varlin -wi-ao---- 20,00g
/dev/md0(28384)
distfiles varlin -wi-a----- 20,00g
/dev/md1(2738)
ftp varlin rwi-aor--- 10,00g 100,00
ftp_rimage_0(0),ftp_rimage_1(0)
ftpdown varlin rwi-aor--- 10,00g 100,00
ftpdown_rimage_0(0),ftpdown_rimage_1(0)
lvm2: 2.02.116
kernel: 4.4.2
1) What I did wrong?
2) Is it possible to salvage /dev/varlin/distfiles or I must restore
it from backups?
3) What I should do now to get system to safe state?
Best regards,
Raimonds Cicans
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