Friday 25 May 2012

Using LVM to create new disks, physical volume, logical volume and volume group OEL

New LVM

You’ve worked out how to create a new disk with OVM (honestly, it could be easier!!!)  The placement of options seems non intuitive for me.  Why can’t I be on my virtual machine and say “new disk”?

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Highlight server pools, then goto repositories tab.  Click the repository that you want to add to, choose Virtual Disks and add…  (CRAZY!)

Then once this is done, goto your virtual machine, edit it and assign the disk.  Ensure that the order is correct.

Boot your VM and you’ll see the new disk with fdisk –l

 

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See what disks you are dealing with

[root@e1web2 ~]# fdisk -l

Disk /dev/xvda: 12.8 GB, 12884901888 bytes

255 heads, 63 sectors/track, 1566 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System

/dev/xvda1 * 1 13 104391 83 Linux

/dev/xvda2 14 1305 10377990 83 Linux

/dev/xvda3 1306 1566 2096482+ 82 Linux swap / Solaris

Disk /dev/xvdb: 30.0 GB, 30000000000 bytes

255 heads, 63 sectors/track, 3647 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/xvdb doesn't contain a valid partition table

Create your physical volume

[root@e1web2 ~]# pvcreate /dev/xvdb

Create your volume group (vgu01), remember that this can be over as many physicals volumes as you like

[root@e1web2 ~]# vgcreate vgu01 /dev/xvdb

Volume group "vgu01" successfully created

Create your logical volume, remember that this can be any size from the volume group

[root@e1web2 ~]# vgdisplay

--- Volume group ---

VG Name vgu01

System ID

Format lvm2

Metadata Areas 1

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 1

Act PV 1

VG Size 27.94 GB

PE Size 4.00 MB

Total PE 7152

Alloc PE / Size 0 / 0

Free PE / Size 7152 / 27.94 GB

VG UUID 0W9kEx-CnVq-jxOp-y5AM-qRho-oU65-Fi8LlH

Create your logical volume

[root@e1web2 ~]# lvcreate -l +100%FREE vgu01

Logical volume "lvol0" created

Display logical volumes

[root@e1web2 ~]# lvdisplay

--- Logical volume ---

LV Name /dev/vgu01/lvol0

VG Name vgu01

LV UUID 3mkbqZ-Fgmk-WuH0-2UUM-f196-E1dm-l82GDd

LV Write Access read/write

LV Status available

# open 0

LV Size 27.94 GB

Current LE 7152

Segments 1

Allocation inherit

Read ahead sectors auto

- currently set to 256

Block device 253:0

Scan volume groups

[root@e1web2 ~]# vgscan

Reading all physical volumes. This may take a while...

Found volume group "vgu01" using metadata type lvm2

Activate the volume group

[root@e1web2 ~]# vgchange -ay

1 logical volume(s) in volume group "vgu01" now active

Format the filesystem (ext3 in my case)

[root@e1web2 ~]# mkfs.ext3 /dev/vgu01/lvol0

Create the mount point

[root@e1web2 ~]# mkdir –p /u01

Mount the logical volume (name from lvdisplay)

[root@e1web2 /]# mount /dev/vgu01/lvol0 /u01

Add perm record in fstab

vi /etc/fstab

sysfs /sys sysfs defaults 0 0

proc /proc proc defaults 0 0

LABEL=SWAP-VM swap swap defaults 0 0

/dev/vgu01/lvol0 /u01 ext3 defaults 0 0

Fill the disk!!!

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