Creating a Mount Point after Presenting a LUN from Storage
1. Identify newly added LUN.
2. Create Physical volume(PV)
3. Create Volume Group(VG)
4. Create Logical Volume(LV)
5. Create File system
6. Mount File system
7. Entries in /etc/fstab file.
Here are the Explanations with commands to perform above plan of
action:
Identify newly added LUN
Create a LUN from storage and present to the server on which you want
to assign a new mount point. To detect new LUN on the server use below command,
it will show you all disks presented to the server till now.
#ioscan –fnNC disk
Here:
f:-
Generate a full listing, displaying the module's class, instance
number, hardware path, driver, software state, hardware type, and a
brief description.
n:-
Generate a full listing, displaying the module's class, instance
number, hardware path, driver, software state, hardware type, and a
brief description.
C:- strict the output listing to those devices belonging to the specified class.
N:- Display the agile view of the system hardware.
Below command shows the
difference between persistent DFS and Legacy DSF. In next steps we are going to
use persistent DSF.
#ioscan –m dsf
Persistent DSF Legacy DSF(s)
========================================
/dev/pt/pt4 /dev/rscsi/c0t0d0
/dev/rscsi/c2t0d0
/dev/rscsi/c4t0d0
/dev/rscsi/c6t0d0
/dev/rdisk/disk41 /dev/rdsk/c1t0d0
/dev/rdsk/c3t0d0
/dev/rdsk/c5t0d0
/dev/rdsk/c7t0d0
/dev/rdisk/disk42 /dev/rdsk/c1t0d1
/dev/rdsk/c3t0d1
/dev/rdsk/c5t0d1
/dev/rdsk/c7t0d1
|
To find which disks are not used in the LVM.
#pvdisplay
–l /dev/disk/*
/dev/disk/disk41:LVM_Disk=no
/dev/disk/disk42:LVM_Disk=yes
/dev/disk/disk43:LVM_Disk=yes
/dev/disk/disk44:LVM_Disk=yes
/dev/disk/disk45:LVM_Disk=yes
|
From the above output we are able to find disk41 is not used in LVM.
So we proceed with disk41. And cross check with the size of disk.
#diskinfo /dev/rdisk/disk41
SCSI describe of /dev/rdisk/disk41:
vendor: HP
product id: OPEN-V
type: direct access
size: 56691712 Kbytes
bytes
per sector: 512
|
Output suggests that it is the same size of disk for which we are looking
for. So proceed to next step.
Create Physical volume(PV)
A disk has to be initialized before LVM can use it.
#pvcreate /dev/rdisk/disk41
Physical volume
"/dev/rdisk/disk41" has been successfully created.
|
If disk41 already initialized before then you will get below error
message
# pvcreate: The Physical Volume already
belongs to a Volume Group
|
If you are sure the disk is free you can force the initialization
using the -f option:
#pvcreate –f /dev/rdisk/disk41
Create Volume Group(VG)
Select
a unique minor number for the VG:
# ll /dev/*/group
crw-r--r--
1 root sys 64 0x000000 Apr 4 2010 /dev/vg00/group
crw-r--r--
1 root sys 64 0x010000 Oct 26 15:52 /dev/vg01/group
crw-r--r-- 1 root sys 64 0x020000 Aug
2 15:49 /dev/vg02/group
|
Create the VG control file (group file):
# mkdir /dev/vg03
# mknod /dev/vg03/group c 64 0x030000
Create the VG
#vgcreate -s 256 /dev/vg03 /dev/disk/disk41
Volume
group "/dev/vg03" has been successfully created.
Volume Group configuration for /dev/vg03 has
been saved in /etc/lvmconf/vg03.conf
|
s: Size of physical extend(PE) in MB.
If you have 2 or more PV to add in a VG, you can add them in one go,
just adding next to disk41 with a space.
#vgcreate –s 256 /dev/vg03 /dev/disk/disk41
/dev/disk/disk40
To display VG information
#vgdisplay -v /dev/vg03
--- Volume groups ---
VG Name
/dev/vg03
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 1
Open LV 1
Max PV 16
Cur PV 1
Act PV 1
Max PE per PV 1727
VGDA 2
PE Size
(Mbytes) 256
Total
PE 216
Alloc PE 0
Free
PE 216
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0
VG Version 1.0
VG Max Size 6908g
VG Max Extents 27632
|
Create Logical Volume(LV)
To create a LV from a VG (option: L- assigns Size in MB; l - Assigns size in Number of PE, n – assigns name to LV)
# lvcreate -L 55040 –n
/dev/vg03/lvol1 /dev/vg03
Logical volume "/dev/vg03/lvol1" has
been successfully created with character device "/dev/vg03/lvol1"
Logical volume "/dev/vg03/lvol1" has
been successfully extended.
Volume Group configuration for /dev/vg03 has been
saved in /etc/lvmconf/vg03.conf
|
To display LV information
# lvdisplay -v /dev/vg03/lvol1
--- Logical volumes ---
LV Name
/dev/vg03/lvol1
VG Name
/dev/vg03
LV Permission read/write
LV Status available/syncd
Mirror copies 0
Consistency Recovery MWC
Schedule parallel
LV Size (Mbytes) 55040
Current LE 215
Allocated PE 215
Stripes 0
Stripe Size (Kbytes) 0
Bad block on
Allocation strict
IO Timeout (Seconds) default
|
Create File system
You can use newfs to put a FS onto the LV:
# newfs -F vxfs /dev/vg03/rlvol1
F: - File system type either hfs or vxfs. Nowadays it is always
recommended to use a VxFS (=JFS) filesystem.
Mount File system
Mounting created File System
#mkdir /data
#mount /dev/vg03/lvol1 /data
Use the bdf command to see the mounted file systems
#bdf
Entries in /etc/fstab file
Make entries in /etc/fstab file to make mount point permanent between
reboots. You can do this with below command or open this file with vi editor and
add entries at the end.
# echo “/dev/vg03/lvol1 /data vxfs defaults 0 2” >> /etc/fstab
#vi /etc/fstab
# System /etc/fstab file. Static information about the file systems
# See fstab(4) and sam(1M) for further details on
configuring devices.
/dev/vg00/lvol3 / vxfs delaylog 0 1
/dev/vg00/lvol1 /stand vxfs tranflush 0 1
/dev/vg00/lvol4 /home vxfs delaylog 0 2
/dev/vg00/lvol5 /opt vxfs delaylog 0 2
/dev/vg00/lvol6 /tmp vxfs delaylog 0 2
/dev/vg00/lvol7 /var vxfs delaylog 0 2
/dev/vg00/lvol8 /usr vxfs delaylog 0 2
/dev/vg03/lvol1
/data vxfs defaults 0 2