[linux-lvm] help using LVM & md for RAID10

Alberto beto at kasenna.com
Sat May 10 08:37:05 UTC 2003


Hi,

I'm trying to use LVM together with md. I know you guys don't
recommend this combination, but I need it to get good performance
from our disks plus some protection. This combination used to work
with 0.3, but stop working with the new 1.0.7. I think the problem is
that after rebooting LVM has problem figuring out that it needs to use
md0-3 and not their corresponding part (/dev/sd?).

Have you done this before?

I'm adding the series of commands we used to create the volume, plus
the status after we reboot the machine.

CREATING THE VOLUME

# cat /proc/mdstat
Personalities : [linear] [raid0] [raid1] [raid5] [multipath]
read_ahead 1024 sectors
md4 : active raid0 md3[3] md2[2] md1[1] md0[0]
      143372288 blocks 512k chunks
md3 : active raid1 sdi[1] sdh[0]
      35843584 blocks [2/2] [UU]
md2 : active raid1 sdg[1] sdf[0]
      35843584 blocks [2/2] [UU]
md1 : active raid1 sde[1] sdd[0]
      35843584 blocks [2/2] [UU]
md0 : active raid1 sdc[1] sdb[0]
      35843584 blocks [2/2] [UU]
unused devices: <none>

#dd bs=256k if=/dev/zero of=/dev/md0 count=1000
#dd bs=256k if=/dev/zero of=/dev/md1 count=1000
#dd bs=256k if=/dev/zero of=/dev/md2 count=1000
#dd bs=256k if=/dev/zero of=/dev/md3 count=1000

# pvcreate /dev/md0
pvcreate -- physical volume "/dev/md0" successfully created

# pvcreate /dev/md1
pvcreate -- physical volume "/dev/md1" successfully created

# pvcreate /dev/md2
pvcreate -- physical volume "/dev/md2" successfully created

# pvcreate /dev/md3
pvcreate -- physical volume "/dev/md3" successfully created

# vgcreate vg01 /dev/md[0-3]
vgcreate -- INFO: using default physical extent size 32 MB
vgcreate -- INFO: maximum logical volume size is 2 Terabyte
vgcreate -- doing automatic backup of volume group "vg01"
vgcreate -- volume group "vg01" successfully created and activated

# pvscan
pvscan -- reading all physical volumes (this may take a while...)
pvscan -- ACTIVE   PV "/dev/md0" of VG "vg01" [34.12 GB / 34.12 GB free]

pvscan -- ACTIVE   PV "/dev/md1" of VG "vg01" [34.12 GB / 34.12 GB free]

pvscan -- ACTIVE   PV "/dev/md2" of VG "vg01" [34.12 GB / 34.12 GB free]

pvscan -- ACTIVE   PV "/dev/md3" of VG "vg01" [34.12 GB / 34.12 GB free]

pvscan -- inactive PV "/dev/md4" of VG "vg01" [34.12 GB / 34.12 GB free]

pvscan -- WARNING: physical volume "/dev/sdb" belongs to a meta device
pvscan -- WARNING: physical volume "/dev/sdc" belongs to a meta device
pvscan -- WARNING: physical volume "/dev/sdd" belongs to a meta device
pvscan -- WARNING: physical volume "/dev/sde" belongs to a meta device
pvscan -- WARNING: physical volume "/dev/sdf" belongs to a meta device
pvscan -- WARNING: physical volume "/dev/sdg" belongs to a meta device
pvscan -- WARNING: physical volume "/dev/sdh" belongs to a meta device
pvscan -- WARNING: physical volume "/dev/sdi" belongs to a meta device
pvscan -- total: 13 [170.92 GB] / in use: 13 [170.92 GB] / in no VG: 0
[0]

#lvcreate -i 4 -I 512 -L 130G -n lv01 vg01
lvcreate -- doing automatic backup of "vg01"
lvcreate -- logical volume "/dev/vg01/lv01" successfully created

# vgdisplay -v
--- Volume group ---
VG Name               vg01
VG Access             read/write
VG Status             available/resizable
VG #                  0
MAX LV                256
Cur LV                1
Open LV               0
MAX LV Size           2 TB
Max PV                256
Cur PV                4
Act PV                4
VG Size               136.50 GB
PE Size               32 MB
Total PE              4368
Alloc PE / Size       4160 / 130 GB
Free  PE / Size       208 / 6.50 GB
VG UUID               tXh4cm-QVz6-bT6a-yLRl-PnHc-cY16-72aPfp

--- Logical volume ---
LV Name                /dev/vg01/lv01
VG Name                vg01
LV Write Access        read/write
LV Status              available
LV #                   1
# open                 0
LV Size                130 GB
Current LE             4160
Allocated LE           4160
Stripes                4
Stripe size (KByte)    512
Allocation             next free
Read ahead sectors     1024
Block device           58:0


--- Physical volumes ---
PV Name (#)           /dev/md0 (1)
PV Status             available / allocatable
Total PE / Free PE    1092 / 52

PV Name (#)           /dev/md1 (2)
PV Status             available / allocatable
Total PE / Free PE    1092 / 52

PV Name (#)           /dev/md2 (3)
PV Status             available / allocatable
Total PE / Free PE    1092 / 52

PV Name (#)           /dev/md3 (4)
PV Status             available / allocatable
Total PE / Free PE    1092 / 52

AFTER REBOOT

# pvscan
pvscan -- reading all physical volumes (this may take a while...)
pvscan -- inactive PV "/dev/md0" of VG "vg01" [34.12 GB / 1.62 GB free]
pvscan -- inactive PV "/dev/md1" of VG "vg01" [34.12 GB / 1.62 GB free]
pvscan -- inactive PV "/dev/md2" of VG "vg01" [34.12 GB / 1.62 GB free]
pvscan -- inactive PV "/dev/md3" of VG "vg01" [34.12 GB / 1.62 GB free]
pvscan -- inactive PV "/dev/md4" of VG "vg01" [34.12 GB / 1.62 GB free]
pvscan -- WARNING: physical volume "/dev/sdb" belongs to a meta device
pvscan -- WARNING: physical volume "/dev/sdc" belongs to a meta device
pvscan -- WARNING: physical volume "/dev/sdd" belongs to a meta device
pvscan -- WARNING: physical volume "/dev/sde" belongs to a meta device
pvscan -- WARNING: physical volume "/dev/sdf" belongs to a meta device
pvscan -- WARNING: physical volume "/dev/sdg" belongs to a meta device
pvscan -- WARNING: physical volume "/dev/sdh" belongs to a meta device
pvscan -- WARNING: physical volume "/dev/sdi" belongs to a meta device
pvscan -- total: 13 [170.92 GB] / in use: 13 [170.92 GB] / in no VG: 0
[0]

[root at sculpin root]# vgdisplay -v
--- Volume group ---
VG Name               vg01
VG Access             read/write
VG Status             available/resizable
VG #                  0
MAX LV                256
Cur LV                1
Open LV               0
MAX LV Size           2 TB
Max PV                256
Cur PV                4
Act PV                4
VG Size               136.50 GB
PE Size               32 MB
Total PE              4368
Alloc PE / Size       4160 / 130 GB
Free  PE / Size       208 / 6.50 GB
VG UUID               tXh4cm-QVz6-bT6a-yLRl-PnHc-cY16-72aPfp

--- Logical volume ---
LV Name                /dev/vg01/lv01
VG Name                vg01
LV Write Access        read/write
LV Status              available
LV #                   1
# open                 0
LV Size                130 GB
Current LE             4160
Allocated LE           4160
Stripes                4
Stripe size (KByte)    512
Allocation             next free
Read ahead sectors     1024
Block device           58:0


--- Physical volumes ---
PV Name (#)           /dev/sdc (1)
PV Status             available / allocatable
Total PE / Free PE    1092 / 52

PV Name (#)           /dev/sde (2)
PV Status             available / allocatable
Total PE / Free PE    1092 / 52

PV Name (#)           /dev/sdg (3)
PV Status             available / allocatable
Total PE / Free PE    1092 / 52

PV Name (#)           /dev/sdi (4)
PV Status             available / allocatable
Total PE / Free PE    1092 / 52

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