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lvconvert -m 0 /dev/varlin/distfiles /dev/md0 => zero filled logical volume

linux-lvm Raimonds Cicans 3 participants 6 messages Mar 16, 2016 – Mar 20, 2016

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Raimonds Cicans

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#0 lore raw

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

#1 lore raw
Quoted 31 lines · 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)

Quoted 7 lines

lvm2: 2.02.116
kernel: 4.4.2

Questions:

1) What I did wrong?

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

Quoted 1 line

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.

Quoted 1 line

3) What I should do now to get system to safe state?

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

author
#2 lore raw
Quoted 32 lines · Stuart Gathman
Quoted 31 lines · 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.

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

Quoted 5 lines
Quoted 3 lines

Questions:

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

author
#3 lore raw
In reply to Raimonds Cicans
Quoted 30 lines · 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.

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)

Quoted 4 lines

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

author
#4 lore raw
Quoted 54 lines · Raimonds Cicans
Quoted 31 lines · 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.

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)

Quoted 4 lines

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.

Quoted 11 lines

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

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

#5 lore raw
In reply to Raimonds Cicans
Quoted 11 lines · 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.

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

Quoted 39 lines

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

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