Login or Register to Ask a Question and Join Our Community


Creating file systems (LVM v Multipath)


 
Thread Tools Search this Thread
Operating Systems Linux Creating file systems (LVM v Multipath)
# 1  
Old 09-30-2015
Creating file systems (LVM v Multipath)

Hi all

I have a system running:
Code:
 uname -o
GNU/Linux

that has already some file systems created:
Code:
 df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg_outsystemdb-lv_root
                       50G  2.7G   45G   6% /
tmpfs                  28G   72K   28G   1% /dev/shm
/dev/sda1             485M   38M  422M   9% /boot
/dev/mapper/vg_outsystemdb-lv_home
                      198G  171G   17G  91% /home
/dev/mapper/vg01-lvol1
                      394G  342G   33G  92% /oradata

And there is a need to add one more file system of 500Gb, in which the storage admin has already provided me with.

But I see that the other file systems have their volume group with some nomenclature that I am not aware of it, in term of skills, like:
/dev/mapper/vg, but as far as I know to create a new file system I just have to fdisk -l the required LUN, them choose 8e as the partition type, them pvcreate, vgcreate and lastly lvcreate.
But I am not sure this is the correct procedure, because the other file systems present on the system have this /dev/mapper.
Please correct me if I am wrong with my procedure
# 2  
Old 09-30-2015
What exactly did your system administrator give you and why didn't the system administrator create the file system. Do you have root access?

What does sudo vgdisplay show?
# 3  
Old 09-30-2015
Quote:
Originally Posted by fretagi
Hi all

I have a system running:
Code:
 uname -o
GNU/Linux

that has already some file systems created:
Code:
 df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg_outsystemdb-lv_root
                       50G  2.7G   45G   6% /
tmpfs                  28G   72K   28G   1% /dev/shm
/dev/sda1             485M   38M  422M   9% /boot
/dev/mapper/vg_outsystemdb-lv_home
                      198G  171G   17G  91% /home
/dev/mapper/vg01-lvol1
                      394G  342G   33G  92% /oradata

And there is a need to add one more file system of 500Gb, in which the storage admin has already provided me with.

But I see that the other file systems have their volume group with some nomenclature that I am not aware of it, in term of skills, like:
/dev/mapper/vg, but as far as I know to create a new file system I just have to fdisk -l the required LUN, them choose 8e as the partition type, them pvcreate, vgcreate and lastly lvcreate.
But I am not sure this is the correct procedure, because the other file systems present on the system have this /dev/mapper.
Please correct me if I am wrong with my procedure
It is OK, that's the virtual interface that it is created when you use LVM. When you create a new logical volume these links are created by the kernel based framework device mapper; mapping target devices with its virtual layer table.
For example:
Code:
/dev/mapper/vg_outsystemdb-lv_home

vg_outsystemdb is the name that the administrator chose when creating the volume group, using vgcreate vg_outsystemdb /dev/sd{a,b,...}
It can be any descriptive name, nothing especial.
lv_home is the name when the lv was created using lvcreate -L198G -n lv_home vg_outsystemdb
The -n is for name and it can be any descriptive name, followed by the volume group label.

Now, if you have some block storage of 500G, you can continue the scheme that appears in the df -h output, i.e.
Code:
/dev/mapper/vg01-lvol1

You can create another volume as
Code:
pvcreate /dev/<device_name>
vgcreate vg02 /dev/<device_name>

and
Code:
lvcreate -L<size> -n lvol1 vg02

That will show as /dev/mapper/vg02-lvol1 in your system
Or you can add that block storage to the current group volume
Code:
pvcreate /dev/<device_name>
vgextend vg01 /dev/<device_name>
lvcreate -L<size> -n lvol2 vg01


Last edited by Aia; 09-30-2015 at 09:41 PM..
# 4  
Old 10-01-2015
Other then stuff mentioned here i would like to make a general recommendation regarding disk devices in Linux.

If you present a disk for instance /dev/xxx, create a primary partition /dev/sda1 which you will use in your volume groups / filesystems / ASM and label it like that (LVM label or other) during fdisk operation.

Why partition ?
Initial sectors are for OS information.
Easier to see and correct possible errors which are out of LVM/ASM/filesystem scope.
Disks partitioned are quite obviously used for some service (LVM, ASM etc.), while non-partitioned are not, reducing possible risk of error during administrative work.

Using full devices will work as well on Linux systems, but due to reasons above i would suggest making one primary partition if you intend to use entire disk space.

As for multipath, use /dev/mapper when creating volume groups and such.
Also using sane names for storage luns in /etc/multipath.conf helps e.g /dev/mapper/databaselun looks much more human then /dev/mapper/mpathXY
# 5  
Old 10-01-2015
Please see if this is correct:

1st step:
Code:
 ls /dev/sd*
/dev/sda  /dev/sda1  /dev/sda2  /dev/sdb  /dev/sdb1  /dev/sdc  /dev/sdd  /dev/sde  /dev/sdf  /dev/sdg  /dev/sdh  /dev/sdi  /dev/sdj

2nd step:
Code:
fdisk /dev/sdj
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0xde657be6.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.

Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
         switch off the mode (command 'c') and change display units to
         sectors (command 'u').

Command (m for help):

3rd step:
Code:
Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4):

I am now stuck, because there other file systems on this system with other partitions, so I dont know what number to choose.

Please help
# 6  
Old 10-01-2015
You are in /dev/sdj indicated by fdisk /dev/sdj, therefore you do not have to worry by what partitions are available in the other devices /dev/sdx

fdisk is telling you that there are no partition tables in it:
Code:
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel

Which means you can start choosing number 1 and create your first partition.
This User Gave Thanks to Aia For This Post:
Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. Solaris

Creating multipath device with FC Disks

Hello, I am trying to setup a storage server with salvaged equipments: QSSC-S4R server, with QLogic 2562 FC HBA's Clariion KTN-STL4 4GB FC Enclosures Disks Salvaged from EMC Vmax Disks are 520B sector size so i converted to 512B in linux environment and create multipath successfully. But... (4 Replies)
Discussion started by: amd103
4 Replies

2. UNIX for Dummies Questions & Answers

Question about lvm file creation

Hi, I have below code for disk creation disk_list=$(ls /dev/sd) for disk in $disk_list do pvcreate $i done So what my understanding is first it is checking the disk under /dev sdb,sdc,sdd,...sdz whether 25 disk are existing if not then its creating the 25 physical volume. I... (4 Replies)
Discussion started by: stew
4 Replies

3. Linux

Creating /boot partition for LVM VG

Hi, I have a server booted into sysresccd (mini-linux OS) with 1 40 GB disk attached I am trying to create a volume group and restore another server into the new one However, when I try to create a partition for /boot it seems that my VG in LVM is not recognized anymore These are the... (2 Replies)
Discussion started by: galuzan
2 Replies

4. UNIX for Dummies Questions & Answers

How to convert non LVM root partition to LVM?

Hi Guys, I m using redhat 6, I have installed root partition as non-LVM . Is there any way i can convert it to LVM? (1 Reply)
Discussion started by: pinga123
1 Replies

5. Linux

Creating Filesystem using DD for LVM

I created a new filesystem using dd and mounted: I have a filesystem /FAW with 1Terra space /dev/sdb1 1151331444 24742604 1068104612 3% /FAW Steps I followed to create a new filesystem # dd if=/dev/zero of=/FAW/vms/linux_vm/disk2.img bs=1 count=1024 seek=500G # mke2fs... (10 Replies)
Discussion started by: sriram003
10 Replies

6. HP-UX

How to reduce LVM to create another LVM

Hi, I'm new to HP-UX. I have LVM on /var with 92Gig. I would like to reduce it to create another LVM for Oracle client with 800 meg or so. How to do it. I'm running 11.iv3 Thanks (4 Replies)
Discussion started by: lamoul
4 Replies

7. UNIX for Advanced & Expert Users

Data Recovery from file system overwritten with LVM.

Hey peeps, Here is somethin u might find interestin.... Is it possible to recover data from a partition which used to be an ext3 file sytem with some nice forgotten backups, which now is an lvm partion containg root partition of another OS. :) I couldn't create any mess better than this, can... (2 Replies)
Discussion started by: squid04
2 Replies

8. UNIX for Dummies Questions & Answers

Creating create mirrored disk files systems using mkfs command

What is the correct mkfs syntax to create mirrored disk files systems? I need to make the file system 20gb. For example: machine# mkfs -F ufs /dev/md/dsk/d40 size not specified ufs usage: mkfs special size(sectors) \ -m : dump fs cmd line used to make this partition -V : print this... (4 Replies)
Discussion started by: GLJ@USC
4 Replies

9. Programming

Creating a Unique ID on distributed systems

Hi, How do you actually create a unique ID on a distributed system. I looked at gethostid but the man page says that its not guaranteed to be unique. Also using the IP address does not seem to be a feasible solution. Is there a function call or mechanism by which this is possible when even the... (4 Replies)
Discussion started by: pic
4 Replies

10. UNIX for Dummies Questions & Answers

Creating user ids on multiple systems simultaneously

I am trying to think of a way to create user ids on multiple Linux systems in one fell swoop without logging onto each system indivually. Is there a way to do this with ssh commands? I don't want to use NIS/LDAP solution just a simple shell script utilitarian methodoloy would suffice. Also, I am... (1 Reply)
Discussion started by: darthur
1 Replies
Login or Register to Ask a Question

Featured Tech Videos