Why warning message "device is not properly aligned" is received when creating a thinly provisioned volume in RHS3.0 ?

Solution Verified - Updated -

Environment

  • Red Hat Gluster Server 3.0
  • RAID 6 (12 drives)

Issue

  • Why warning message "device is not properly aligned" is received when creating a thinly provisioned volume in RHS3.0 ?

~ Snippet from terminal:

[root@test ~]# pvcreate --dataalignment 1280K /dev/sdc
  Physical volume "/dev/sdc" successfully created

[root@test ~]# vgcreate --physicalextentsize 128K vg03 /dev/sdc
  Volume group "vg03" successfully created

[root@test ~]# lvcreate -L 16776960K -n lv_meta vg03
  Logical volume "lv_meta" created

[root@test ~]# lvcreate -L 2147482880K -n lv_pool vg03
  Logical volume "lv_pool" created

[root@test ~]# lvconvert --chunksize=1280K --thinpool vg03/lv_pool --poolmetadata vg03/lv_meta  WARNING: Converting logical volume vg03/lv_pool and vg03/lv_meta to pool's data and metadata volumes.
  THIS WILL DESTROY CONTENT OF LOGICAL VOLUME (filesystem etc.)
Do you really want to convert vg03/lv_pool and vg03/lv_meta? [y/n]: y
  Logical volume "lvol0" created
  WARNING: Pool zeroing and large 1.25 MiB chunk size slows down provisioning.
  Converted vg03/lv_pool to thin pool.

[root@test ~]#  lvchange --zero n vg03/lv_pool
Logical volume "lv_pool" changed.

[root@test ~]# lvcreate -V 2147482880K-T vg03/lv_pool -n lv_volume
  Logical volume "lv_volume" created

[root@test ~]#  mkfs -t xfs -i size=512 -n size=8192 -d su=128k,sw=10 /dev/vg03/lv_volume
warning: device is not properly aligned /dev/vg03/lv_volume
Use -f to force usage of a misaligned device

Resolution

  • Issue is fixed when the thin pool is created using a physical volume on a disk partition (/dev/sdc1) instead of using a raw disk/volume (/dev/sdc).

Diagnostic Steps

Steps to Reproduce:

1. pvcreate /dev/device
2. vgcreate vg03 /dev/device
3. Create thin pool,

lvcreate -L <thinpool_size> -T vg03/thinpool

4. Create thin pool volume,

lvcreate -V <thin_volume_size_from_thinpool> -T vg03/thinpool -n thinvolume

5. Format the thin pool volume with xfs,

mkfs -t xfs -i size=512 -n size=8192 -d su=128k,sw=10 /dev/vg03/thinvolume

Test Output:

# cat /etc/redhat-storage-release 
Red Hat Storage Server 3.0 Update 3

# uname -r
2.6.32-504.el6.x86_64

[root@rhs3_geo_rep_node2 ~]# lvconvert --chunksize=1280K --thinpool vg03/lv_pool
  WARNING: Converting logical volume vg03/lv_pool to pool's data volume.
  THIS WILL DESTROY CONTENT OF LOGICAL VOLUME (filesystem etc.)
Do you really want to convert vg03/lv_pool? [y/n]: y
  Logical volume "lvol0" created
  Logical volume "lvol0" created
  WARNING: Pool zeroing and large 1.25 MiB chunk size slows down provisioning.
  Converted vg03/lv_pool to thin pool.

[root@rhs3_geo_rep_node2 ~]# lvchange --zero n vg03/lv_pool
  Logical volume "lv_pool" changed.

[root@rhs3_geo_rep_node2 ~]# lvcreate -V 9G -T vg03/lv_pool -n lv_volume
  Rounding size (73728 extents) up to chunk boundary size (73730 extents).
  Logical volume "lv_volume" created

[root@rhs3_geo_rep_node2 ~]# mkfs -t xfs -i size=512 -n size=8192 -d su=128k,sw=10 /dev/vg03/lv_volume 
warning: device is not properly aligned /dev/vg03/lv_volume
Use -f to force usage of a misaligned device

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