Tutorial News Comments FAQ Related Articles

How To Manage Multiple LVM Disk Using Striping IO

{{postValue.id}}

To Manage Multiple Logical Volume Management Disks using Striping IO

Logical Volume Management Stripping allows to write data over multiple disk which in-turn increases the performance and efficiency of the disk. Managing Multiple LVM Disk Using Stripping IO is discussed in this manual.

Features

  • Increase the performance of disk.
  • Saves from hard write over to a single disk.
  • Reduce disk fill-up using striping over multiple disk.

Manage Logical Volume using Striping I/O

We have totally 6 hard disk and sda hard disk is used by the system OS. Run the following command to list the devices as shown below.

[root@linuxhelp ~]# ls -l /dev | grep sd
brw-rw----. 1 root disk      8,   0 Apr 26 12:22 sda
brw-rw----. 1 root disk      8,   1 Apr 26 12:22 sda1
brw-rw----. 1 root disk      8,   2 Apr 26 12:22 sda2
brw-rw----. 1 root disk      8,   3 Apr 26 12:22 sda3
brw-rw----. 1 root disk      8,  16 Apr 26 12:25 sdb
brw-rw----. 1 root disk      8,  17 Apr 26 12:25 sdb1
brw-rw----. 1 root disk      8,  32 Apr 26 12:26 sdc
brw-rw----. 1 root disk      8,  33 Apr 26 12:26 sdc1
brw-rw----. 1 root disk      8,  48 Apr 26 12:26 sdd
brw-rw----. 1 root disk      8,  49 Apr 26 12:26 sdd1
brw-rw----. 1 root disk      8,  64 Apr 26 12:27 sde
brw-rw----. 1 root disk      8,  65 Apr 26 12:27 sde1
brw-rw----. 1 root disk      8,  80 Apr 26 12:28 sdf
brw-rw----. 1 root disk      8,  81 Apr 26 12:28 sdf1

We have created partitions for these 5 hard drives sdb, sdc, sdd, sde and sdf each of size 2 GB using ‘ fdisk‘ command.

[root@linuxhelp ~]# fdisk -l | grep sd
Disk /dev/sdd: 4294 MB, 4294967296 bytes, 8388608 sectors
/dev/sdd1            2048     4196351     2097152   8e  Linux LVM
Disk /dev/sdc: 4294 MB, 4294967296 bytes, 8388608 sectors
/dev/sdc1            2048     4196351     2097152   8e  Linux LVM
Disk /dev/sde: 4294 MB, 4294967296 bytes, 8388608 sectors
/dev/sde1            2048     4196351     2097152   8e  Linux LVM
Disk /dev/sda: 32.2 GB, 32212254720 bytes, 62914560 sectors
/dev/sda1   *        2048      616447      307200   83  Linux
/dev/sda2          616448     4810751     2097152   82  Linux swap / Solaris
/dev/sda3         4810752    35530751    15360000   83  Linux
Disk /dev/sdb: 4294 MB, 4294967296 bytes, 8388608 sectors
/dev/sdb1            2048     4196351     2097152   8e  Linux LVM
Disk /dev/sdf: 4294 MB, 4294967296 bytes, 8388608 sectors
/dev/sdf1            2048     4196351     2097152   8e  Linux LVM


For more information about the fdisk, use the following link.
www.linuxhelp.com/fdisk-command

To create Physical volumes

Use the following command to create physical volumes as shown below,

[root@linuxhelp ~]# pvcreate /dev/sd[b-f]1 -v
    Set up physical volume for " /dev/sdb1"  with 4194304 available sectors
    Zeroing start of device /dev/sdb1
    Writing physical volume data to disk " /dev/sdb1" 
  Physical volume " /dev/sdb1"  successfully created
    Set up physical volume for " /dev/sdc1"  with 4194304 available sectors
    Zeroing start of device /dev/sdc1
    Writing physical volume data to disk " /dev/sdc1" 
  Physical volume " /dev/sdc1"  successfully created
    Set up physical volume for " /dev/sdd1"  with 4194304 available sectors
    Zeroing start of device /dev/sdd1
    Writing physical volume data to disk " /dev/sdd1" 
  Physical volume " /dev/sdd1"  successfully created
    Set up physical volume for " /dev/sde1"  with 4194304 available sectors
    Zeroing start of device /dev/sde1
    Writing physical volume data to disk " /dev/sde1" 
  Physical volume " /dev/sde1"  successfully created
    Set up physical volume for " /dev/sdf1"  with 4194304 available sectors
    Zeroing start of device /dev/sdf1
    Writing physical volume data to disk " /dev/sdf1" 
  Physical volume " /dev/sdf1"  successfully created

Run the following command to list the physical volumes that we have created.

[root@linuxhelp ~]# pvs
  PV         VG   Fmt  Attr PSize PFree
  /dev/sdb1       lvm2 a--  2.00g 2.00g
  /dev/sdc1       lvm2 a--  2.00g 2.00g
  /dev/sdd1       lvm2 a--  2.00g 2.00g
  /dev/sde1       lvm2 a--  2.00g 2.00g
  /dev/sdf1       lvm2 a--  2.00g 2.00g

Now create volume group using those 5 physical volumes by executing the following command.

[root@linuxhelp ~]# vgcreate -s 32M vg1 /dev/sd[b-f]1 -v
    Adding physical volume ' /dev/sdb1'  to volume group ' vg1' 
    Adding physical volume ' /dev/sdc1'  to volume group ' vg1' 
    Adding physical volume ' /dev/sdd1'  to volume group ' vg1' 
    Adding physical volume ' /dev/sde1'  to volume group ' vg1' 
    Adding physical volume ' /dev/sdf1'  to volume group ' vg1' 
    Archiving volume group " vg1"  metadata (seqno 0).
    Creating volume group backup " /etc/lvm/backup/vg1"  (seqno 1).
  Volume group " vg1"  successfully created

Explanation
[b-e]1 &ndash It defines our hard drive names such as sdb1, sdc1, sdd1, sde1.
-s &ndash It defines our physical extent size.
-v &ndash verbose.

Use vgdisplay command to know more information about Volume Group ' vg1' .

[root@linuxhelp ~]# vgdisplay vg1 -v
    Using volume group(s) on command line
    Finding volume group " vg1" 
  --- Volume group ---
  VG Name               vg1
  System ID             
  Format                lvm2
  Metadata Areas        5
  Metadata Sequence No  1
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                0
  Open LV               0
  Max PV                0
  Cur PV                5
  Act PV                5
  VG Size               9.84 GiB
  PE Size               32.00 MiB
  Total PE              315
  Alloc PE / Size       0 / 0   
  Free  PE / Size       315 / 9.84 GiB
  VG UUID               CEIF1J-mwTn-Rb0r-azea-q8dy-O4lL-VzhbBb
   
  --- Physical volumes ---
  PV Name               /dev/sdb1     
  PV UUID               y6agXC-Ug7z-1BOL-oo6T-KOjz-47Zd-gpSeBW
  PV Status             allocatable
  Total PE / Free PE    63 / 63
   
  PV Name               /dev/sdc1     
  PV UUID               R2pgW0-fpvg-hHS7-A3i2-VcGX-9WVc-7FBVOY
  PV Status             allocatable
  Total PE / Free PE    63 / 63
   
  PV Name               /dev/sdd1     
  PV UUID               2N7Umt-kQNE-gVRU-Fywd-x3VP-PBkH-e9o7qB
  PV Status             allocatable
  Total PE / Free PE    63 / 63
   
  PV Name               /dev/sde1     
  PV UUID               B2vTHA-Ec1E-3xgs-VLdi-ew2d-9LbX-TqYWlL
  PV Status             allocatable
  Total PE / Free PE    63 / 63
   
  PV Name               /dev/sdf1     
  PV UUID               eCYQGq-WRco-I20r-mmVd-kBHL-MEBY-vd2rdm
  PV Status             allocatable
  Total PE / Free PE    63 / 63

To Create Logical Volume

Create Logical volume, by defining the stripe value as shown below.

[root@linuxhelp ~]# lvcreate -L 1.5G -n lv1 -i5 vg1
  Using default stripesize 64.00 KiB
  Rounding size (48 extents) up to stripe boundary size (50 extents).
  Logical volume " lv1"  created

Explanation
-L is the logical volume size
-n is the logical volume name
-i is the stripes

The above output shows that the default stripe-size is 64 KB.

Run the following command to check the logical volumes.

[root@linuxhelp ~]# lvdisplay vg1/lv1 -m
  --- Logical volume ---
  LV Path                /dev/vg1/lv1
  LV Name                lv1
  VG Name                vg1
  LV UUID                d1F6Fa-a6sd-8ydc-WufU-BWCu-t18c-FLdvS4
  LV Write Access        read/write
  LV Creation host, time linuxhelp, 2016-04-26 12:50:48 +0530
  LV Status              available
  # open                 0
  LV Size                1.56 GiB
  Current LE             50
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     1280
  Block device           253:0
   
  --- Segments ---
  Logical extent 0 to 49:
    Type        striped
    Stripes        5
    Stripe size        64.00 KiB
    Stripe 0:
      Physical volume    /dev/sdb1
      Physical extents    0 to 9
    Stripe 1:
      Physical volume    /dev/sdc1
      Physical extents    0 to 9
    Stripe 2:
      Physical volume    /dev/sdd1
      Physical extents    0 to 9
    Stripe 3:
      Physical volume    /dev/sde1
      Physical extents    0 to 9
    Stripe 4:
      Physical volume    /dev/sdf1
      Physical extents    0 to 9

Now we will define a stripe with the customized size of 256 KB and logical volume of 2 GB using the following command.

[root@linuxhelp ~]# lvcreate -L 2G -i4 -I 256 -n lv2 vg1 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1
  Logical volume " lv2"  created

The Logical volume was created. Lets display it by using the following command.

[root@linuxhelp ~]# lvdisplay vg1/lv2 -m
  --- Logical volume ---
  LV Path                /dev/vg1/lv2
  LV Name                lv2
  VG Name                vg1
  LV UUID                Ypfe9c-pAu9-2rjy-0NE4-Rz87-hWJq-MNs26Z
  LV Write Access        read/write
  LV Creation host, time linuxhelp, 2016-04-26 12:59:28 +0530
  LV Status              available
  # open                 0
  LV Size                2.00 GiB
  Current LE             64
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     4096
  Block device           253:1
   
  --- Segments ---
  Logical extent 0 to 63:
    Type        striped
    Stripes        4
    Stripe size        256.00 KiB
    Stripe 0:
      Physical volume    /dev/sdb1
      Physical extents    10 to 25
    Stripe 1:
      Physical volume    /dev/sdc1
      Physical extents    10 to 25
    Stripe 2:
      Physical volume    /dev/sdd1
      Physical extents    10 to 25
    Stripe 3:
      Physical volume    /dev/sde1
      Physical extents    10 to 25

Check the dependency of the strips by using the following ' dmsetup' command.

[root@linuxhelp ~]# dmsetup deps /dev/vg1/lv[1-2]
/dev/vg1/lv1: 5 dependencies    : (8, 81) (8, 65) (8, 49) (8, 33) (8, 17)
/dev/vg1/lv2: 4 dependencies    : (8, 65) (8, 49) (8, 33) (8, 17)

The above result shows that stripe 1 depends on 5 drives and stripe 2 depends on 4 devices.

Tags:
Author: 

Comments ( 0 )

No comments available

Frequently asked questions ( 5 )

Q

How are snapshots in LVM2 different from LVM1?

A

In LVM2 snapshots are read/write by default, whereas in LVM1, snapshots were only read-only.

Q

Is it possible to increase the logical volume on the process in lvm?

A

Yes. We can increase the logical volume without umount it.

Q

How to see the detailed physical volume information in lvm?

A

This command will show the details of the pv
Use “pvdisplay /dev/disk_name” Ex: pvdisplay /dev/sde

Q

How to extend the volume group in lvm?

A

By using this command you can extend
Syntax: "vgexten" we can increase the volume group.

Q

How to disable the volume group in lvm?

A

By using this command to disable the VG
Syntax:"vgchange -an volume_group_name".

Back To Top!