Physical Volume Create Conundrum Post: 302852463

Sponsored Content

Operating Systems Linux Red Hat Physical Volume Create Conundrum Post 302852463 by scotbuff on Wednesday 11th of September 2013 03:34:18 PM

09-11-2013

Registered User

Physical Volume Create Conundrum

I want to start by saying I already resolved my issue but I want to understand why I am seeing what I am seeing.

I have a server with a RAID controller two 500GB drives and six 600GB drives. The two 500GB drives are mirrored and have the OS installed on them. The six 600GB they wanted set as RAID0 and wanted them in a new volume group. My issue was getting the full size out of the RAID0 Virtual Disk.

On boot I saw the disk:
sd 0:2:1:0: [sdb] 7025983488 512-byte logical blocks: (3.59 TB/3.27 TiB)

I work mostly with LUNs and generally I can just do a pvcreate and I am ready to use the disk. But I could not issue a pvcreate on /dev/sdb and it seemed to need to be partitioned. So I used fdisk using this procedure, which I found to be the same on Red Hat's website:
Create Linux Partition

Once I had a partition I was issuing a pvcreate /dev/sdb1 and each time I ended up with only 2TB of usable space.

Code:

[root@testserv dev]# pvcreate /dev/sdb1
  Physical volume "/dev/sdb1" successfully created
[root@testserv dev]# pvscan
  PV /dev/sda2   VG vg01            lvm2 [464.75 GiB / 355.75 GiB free]
  PV /dev/sdb1                      lvm2 [2.00 TiB]

I ended up just issuing a pvremove, removing the partition and issueing a vgcreate against the raw device. I noticed that the vgcreate created the physical volume for me and it was the correct size.

Code:

[root@testserv ~]# vgcreate scratchvg /dev/sdb
  No physical volume label read from /dev/sdb
  Physical volume "/dev/sdb" successfully created
  Volume group "scratchvg" successfully created
[root@testserv ~]# pvscan
  PV /dev/sdb    VG scratchvg   lvm2 [3.27 TiB / 3.27 TiB free]
  PV /dev/sda2   VG vg01        lvm2 [464.75 GiB / 355.75 GiB free]
  Total: 2 [3.73 TiB] / in use: 2 [3.73 TiB] / in no VG: 0 [0   ]

My question is, what am I missing? I am completely fine with just skipping the fdisk and pvcreate steps but I thought I had to do those steps. What was I doing wrong? What is the proper procedure when taking a Virtual Disk presented by a RAID controller and creating or adding it to a volume group? I guess my own answer would be the procedure that works, but since I found so many references to using fdisk and partitioning the disk I am curious why that was not working for me. Thanks.

scotbuff

View Public Profile for scotbuff

Find all posts by scotbuff

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

physical volume and physical disk.

Hello, I need explanations about physical disks and physical volumes. What is the difference between these 2 things? In fact, i am trying to understand what the AIX lspv2command does. Thank you in advance.

2. UNIX for Dummies Questions & Answers

Physical volume- no free physical partitions

I was in smit, checking on disc space, etc. and it appears that one of our physical volumes that is part of a large volume group, has no free physical partitions. The server is running AIX 5.1. What would be the advisable step to take in this instance?

3. AIX

Basic Filesystem / Physical Volume / Logical Volume Check

Hi! Can anyone help me on how I can do a basic check on the Unix filesystems / physical volumes and logical volumes? What items should I check, like where do I look at in smit? Or are there commands that I should execute? I need to do this as I was informed by IBM that there seems to be...

4. UNIX for Dummies Questions & Answers

trying to devide existing physical volume

hi guys, i`m trying to take 40GB of my sda5 (/home mounted) to create new volume group(lvc) here`s the df output: /dev/sda2 7,9G 3,3G 4,3G 44% / udevfs 5,0M 60K 5,0M 2% /dev shmfs 379M 0 379M 0% /dev/shm tmpfs 379M ...

5. AIX

How to determine the physical volume fo the disks

This is the report I got running the comand rptconf, but I would like to know what is the capacity of the disks installed into our server power 6 with AIX System Model: IBM,7778-23X Machine Serial Number: 1066D5A Processor Type: PowerPC_POWER6 Processor Implementation Mode: POWER 6...

6. UNIX for Dummies Questions & Answers

importing a Physical Volume

hi guys I'm added a new disk to my server (virtual environment) It used to be a Volume Group=Vol_Group01 and Logical Volume= Log_Vol_01_Data and I see /dev/sdb Disk /dev/sdb doesn't contain a valid partition table Disk /dev/sdc: 133.1 GB, 133143986176 bytes 255 heads, 63...

7. UNIX for Dummies Questions & Answers

Confusion Regarding Physical Volume,Volume Group,Logical Volume,Physical partition

Hi, I am new to unix. I am working on Red Hat Linux and side by side on AIX also. After reading the concepts of Storage, I am now really confused regarding the terminologies 1)Physical Volume 2)Volume Group 3)Logical Volume 4)Physical Partition Please help me to understand these concepts.

8. Red Hat

Create volume using LVM over 2 physical disks

I wanted to know how we can combine volumes over 2 physical drives. # fdisk -l Disk /dev/sda: 42.9 GB, 42949672960 bytes 255 heads, 63 sectors/track, 5221 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sda1 ...

9. AIX

Position of the logical volume on the physical volume

Hello everyone, I just read that while creating a logical volume(LV) we can choose the region of the physical volume (PV) in which the LV should be created. When I say region I mean: outer edge - outer middle - center - inner middle and inner edge. Can anyone help me understand the utility...

10. Red Hat

No space in volume group. How to create a file system using existing logical volume

Hello Guys, I want to create a file system dedicated for an application installation. But there is no space in volume group to create a new logical volume. There is enough space in other logical volume which is being mounted on /var. I know we can use that logical volume and create a virtual...

LEARN ABOUT SUNOS

vgextend

VGEXTEND(8)						      System Manager's Manual						       VGEXTEND(8)

NAME

       vgextend - add physical volumes to a volume group

SYNOPSIS

       vgextend  [-A|--autobackup  y|n]  [-d|--debug]  [-h|-?|--help] [--restoremissing] [-f|--force] [-t|--test] [-v|--verbose] [ PHYSICAL DEVICE
       OPTIONS ] VolumeGroupName PhysicalDevicePath [PhysicalDevicePath...]

DESCRIPTION

       vgextend allows you to add one or more initialized physical volumes ( see pvcreate(8) ) to an existing volume group to extend it  in  size.
       Moreover,  it  allows  you to re-add a physical volume that has gone missing previously, due to a transient device failure, without re-ini-
       tialising it. Use vgextend --restoremissing to that effect.

       If PhysicalDevicePath was not previously configured for LVM with pvcreate (8), the device will be initialized with the same default  values
       used  with  pvcreate.  If non-default pvcreate values are are desired, they may be given on the commandline with the same options as pvcre-
       ate.  See PHYSICAL DEVICE OPTIONS for available options.  Note that the restore-related options such as --restorefile, --uuid, and --physi-
       calvolumesize are not available.  If a restore operation is needed, use pvcreate (8) and vgcfgrestore (8).

OPTIONS

       See lvm for common options.

PHYSICAL DEVICE OPTIONS

       The  following  options	are  available	for initializing physical devices in the volume group.	These options are further described in the
       pvcreate man page.

       -f, --force

       -y, --yes

       -Z, --zero y|n

       --labelsector sector

       --metadatasize size

       [--metadataignorey|n]

       --pvmetadatacopies copies

       --dataalignment alignment

       --dataalignmentoffset alignment_offset

Examples
       "vgextend vg00 /dev/sda4 /dev/sdn1" tries to extend the existing volume group "vg00"  by  the  new  physical  volumes  (see  pvcreate(8)  )
       "/dev/sdn1" and /dev/sda4".

SEE ALSO

       lvm(8), vgcreate(8), vgreduce(8), pvcreate(8)

Sistina Software UK					 LVM TOOLS 2.02.95(2) (2012-03-06)					       VGEXTEND(8)

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

physical volume and physical disk.

Discussion started by: VeroL

2. UNIX for Dummies Questions & Answers

Physical volume- no free physical partitions

Discussion started by: markper

3. AIX

Basic Filesystem / Physical Volume / Logical Volume Check

Discussion started by: chipahoys

4. UNIX for Dummies Questions & Answers

trying to devide existing physical volume

Discussion started by: neverhood