LVM

[Indrajit Bhagat]

Like in Linux , We use fdisk command to know how many physical disk are installed and we get the /dev/hda for one physical disk and /dev/hdb for second physical disk,
than what is similar command in HP UNIx

[Ivan Krastev · Accepted solution]

Use ioscan:


ioscan -fnC disk


regards,
ivan

[Coolmar]

ioscan -fnC disk

This will list all your disks and corresponding devices.

[Indrajit Bhagat]

Then please Guide me how Pvcreate and Pvdisplay command can be executed.

[Torsten.]

Hi,

at least until now (HP-UX 11.23) the concept is different.

The disks are not "counted" (a,b,c,... or 1,2,3 ...).

If you run "ioscan -fnCdisk" or "ioscan -fnkCdisk" you will get a hw-path and device files.

The device file looks like this example:

/dev/dsk/c10t3d0

For a simple SCSI connected disk this means
the disk is connected to controller 10 (c10) (the HW path will tell you the slot where the HBA is installed),
the disks has SCSI ID 3 (t3) and the LUM number is 0 (d0).

Note, array LUNs will be translated to look like this, but the d-value will become important.

[Coolmar]

pvcreate will create a Physical Volume.

# pvcreate /dev/dsk/c0t0d1

pvdisplay will display information about the physical volume.

So if you are wanting to create a volume group; then a logical volume; and then a filesystem like /oracle for example - here are the steps:

Search for attached disk

# ioscan -fnC disk

Initialize a disk for use with LVM

# pvcreate -f /dev/rdsk/c0t1d0

Create the device structure needed for a new volume group.

# cd /dev
# mkdir vgdata
# cd vgdata
# mknod group c 64 0x010000

Create volume group vgdata

# vgcreate vgdata /dev/dsk/c0t1d0
( if your expecting to use more than 16 physical disks use the -p option, range from 1 to 256 disks. }

Display volume group vgdata

# vgdisplay -v vg01

Add another disk to volume group

# pvcreate -f /dev/rdsk/c0t4d0

# vgextend vg01 /dev/dsk/c0t4d0

Create a 100 MB logical volume lvdata

#lvcreate -L 100 -n lvdata vgdata
# newfs -F vxfs /dev/vgdata/rlvdata
# mount /lvdata

[Indrajit Bhagat]

this is output which i get
# ioscan -funC disk
Class I H/W Path Driver S/W State H/W Type Description
=========================================================================
disk 3 0/0/1/1.0.0 sdisk CLAIMED DEVICE HP 36.4GMAS3367NC
/dev/dsk/c1t0d0 /dev/rdsk/c1t0d0
disk 0 0/0/1/1.2.0 sdisk CLAIMED DEVICE HP 36.4GMAS3367NC
/dev/dsk/c1t2d0 /dev/rdsk/c1t2d0
disk 4 0/0/2/0.0.0 sdisk CLAIMED DEVICE HP 36.4GMAS3367NC
/dev/dsk/c2t0d0 /dev/rdsk/c2t0d0
disk 1 0/0/2/0.2.0 sdisk CLAIMED DEVICE HP 36.4GMAS3367NC
/dev/dsk/c2t2d0 /dev/rdsk/c2t2d0
disk 2 0/0/2/1.2.0 sdisk CLAIMED DEVICE HP DVD-ROM 305
/dev/dsk/c3t2d0 /dev/rdsk/c3t2d0
disk 6 0/10/0/0.1.0.42.0.0.0 sdisk CLAIMED DEVICE HP A6189B
/dev/dsk/c5t0d0 /dev/rdsk/c5t0d0
disk 8 0/10/0/0.1.0.42.0.0.1 sdisk CLAIMED DEVICE HP A6189B
/dev/dsk/c5t0d1 /dev/rdsk/c5t0d1
disk 10 0/10/0/0.1.0.42.0.0.2 sdisk CLAIMED DEVICE HP A6189B
/dev/dsk/c5t0d2 /dev/rdsk/c5t0d2
disk 12 0/10/0/0.1.0.42.0.0.3 sdisk CLAIMED DEVICE HP A6189B
/dev/dsk/c5t0d3 /dev/rdsk/c5t0d3
disk 5 0/12/0/0.1.0.39.0.0.0 sdisk CLAIMED DEVICE HP A6189B
/dev/dsk/c4t0d0 /dev/rdsk/c4t0d0
disk 7 0/12/0/0.1.0.39.0.0.1 sdisk CLAIMED DEVICE HP A6189B
/dev/dsk/c4t0d1 /dev/rdsk/c4t0d1
disk 9 0/12/0/0.1.0.39.0.0.2 sdisk CLAIMED DEVICE HP A6189B
/dev/dsk/c4t0d2 /dev/rdsk/c4t0d2
disk 11 0/12/0/0.1.0.39.0.0.3 sdisk CLAIMED DEVICE HP A6189B
/dev/dsk/c4t0d3 /dev/rdsk/c4t0d3

Then how to execute Pvcreate and pvdisplay

[Coolmar]

Sorry, should have mentioned above that you can also do everything from the menu interface SAM. Type SAM at the command line and then go into Disks and Filesystems...from there you can see all your disks and then create a volume group, create your logical volume, and then the filesystem. I found it easier to physically see everthing layed out when I was first familiarizing myself with LVM.

[Coolmar]

# pvdisplay /dev/dsk/c1t0d0
# pvcreate -f /dev/rdsk/c1t0d0

** Notice that you require the raw device for the pvcreate command

[Torsten.]

You will find all important documentation on http://docs.hp.com - please have a look!

From your ioscan:

disk 6 0/10/0/0.1.0.42.0.0.0 sdisk CLAIMED DEVICE HP A6189B
/dev/dsk/c5t0d0 /dev/rdsk/c5t0d0
disk 8 0/10/0/0.1.0.42.0.0.1 sdisk CLAIMED DEVICE HP A6189B
/dev/dsk/c5t0d1 /dev/rdsk/c5t0d1
disk 10 0/10/0/0.1.0.42.0.0.2 sdisk CLAIMED DEVICE HP A6189B
/dev/dsk/c5t0d2 /dev/rdsk/c5t0d2
disk 12 0/10/0/0.1.0.42.0.0.3 sdisk CLAIMED DEVICE HP A6189B
/dev/dsk/c5t0d3 /dev/rdsk/c5t0d3
disk 5 0/12/0/0.1.0.39.0.0.0 sdisk CLAIMED DEVICE HP A6189B
/dev/dsk/c4t0d0 /dev/rdsk/c4t0d0
disk 7 0/12/0/0.1.0.39.0.0.1 sdisk CLAIMED DEVICE HP A6189B
/dev/dsk/c4t0d1 /dev/rdsk/c4t0d1
disk 9 0/12/0/0.1.0.39.0.0.2 sdisk CLAIMED DEVICE HP A6189B
/dev/dsk/c4t0d2 /dev/rdsk/c4t0d2
disk 11 0/12/0/0.1.0.39.0.0.3 sdisk CLAIMED DEVICE HP A6189B
/dev/dsk/c4t0d3 /dev/rdsk/c4t0d3


I see you are using a VA virtual array. I assume your

c5tydz

and

c4tydz

devices are the same (alternate pathes).

So be careful. For this time I would recommend to use SAM, but it is important for you to understand the concept.
Just start SAM, go to disk devices and create a new volume group and logical volumes and mount points.

[Sp4admin]

Hello,

THe command i use is "ioscan -fnC disk" to show the hardware path and disk /dev devices. You also need to make sure the hardware is claimed.

sp,

[Indrajit Bhagat]

Suppose I wants to create a Logical Volume with any particular logical volume then what would be the command.

[Ganesh Balraman]

Step 1 : Run ioscan and find out the deivce name.


Step2 : Vgcreate for one hard disk

Step3: Vgextend for another disk (Same device number).

This method is called alternate link configuaration.

[Coolmar]

Create a 100 MB logical volume lvdata

Create a 100 MB logical volume lvdata

#lvcreate -L 100 -n lvdata vgdata
# newfs -F vxfs /dev/vgdata/rlvdata
# mount /lvdata

So in the above steps a 100MB logical volume was created in the vgdata volume group and mounted as /lvdata