How to create logical volumes in linux

This example procedure creates an LVM logical volume called new_logical_volume that consists of the disks at /dev/sda1, /dev/sdb1, and /dev/sdc1.

1. To use disks in a volume group, label them as LVM physical volumes with the pvcreatecommand.
   WARNING

   This command destroys any data on /dev/sda1, /dev/sdb1, and /dev/sdc1.

   # pvcreate /dev/sda1 /dev/sdb1 /dev/sdc1
     Physical volume "/dev/sda1" successfully created
     Physical volume "/dev/sdb1" successfully created
     Physical volume "/dev/sdc1" successfully created
   

2. #Another Example:
   
   pvcreate /dev/mapper/mpathx
   

3. Create the a volume group that consists of the LVM physical volumes you have created. The following command creates the volume group new_vol_group.

   # vgcreate new_vol_group /dev/sda1 /dev/sdb1 /dev/sdc1
     Volume group "new_vol_group" successfully created
   

   You can use the vgs command to display the attributes of the new volume group.

   # vgs
     VG            #PV #LV #SN Attr   VSize  VFree
     new_vol_group   3   0   0 wz--n- 51.45G 51.45G
   

4. Create the logical volume from the volume group you have created. The following command creates the logical volume new_logical_volume from the volume group new_vol_group. This example creates a logical volume that uses 2 gigabytes of the volume group.

   # lvcreate -L 2 G -n new_logical_volume new_vol_group
     Logical volume "new_logical_volume" created

5. 
   
   #Another Example:
   
    lvcreate -l 100%FREE -n new_logical_volume new_vol_group
   
   
   

6. Create a file system on the logical volume. The following command creates a GFS2 file system on the logical volume.

   # mkfs.gfs2 -p lock_nolock -j 1 /dev/new_vol_group/new_logical_volume
   This will destroy any data on /dev/new_vol_group/new_logical_volume.
   
   Are you sure you want to proceed? [y/n] y
   
   Device:                    /dev/new_vol_group/new_logical_volume
   Blocksize:                 4096
   Filesystem Size:           491460
   Journals:                  1
   Resource Groups:           8
   Locking Protocol:          lock_nolock
   Lock Table:
   
   Syncing...
   All Done
   
   #Another Example:
   
   mkfs.xfs /dev/vgx/lgx
   mkfs.xfs /dev/mapper/vg..

   The following commands mount the logical volume and report the file system disk space usage.

   # mount /dev/new_vol_group/new_logical_volume /mnt
   # df
   Filesystem           1K-blocks      Used Available Use% Mounted on
   /dev/new_vol_group/new_logical_volume
                          1965840        20   1965820   1% /mnt
   

https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Logical_Volume_Manager_Administration/LVM_examples.html






Fiziksel diskler atandıktan sonra scan işlemi yapılır


echo "- - -" > /sys/class/scsi_host/host0/scan
echo "- - -" > /sys/class/scsi_host/host1/scan
echo "- - -" > /sys/class/scsi_host/host2/scan


fdisk -l ile disklerin mpathx bilgileri not edilir


[root@servername /]# pvcreate /dev/mapper/mpathae /dev/mapper/mpathaf
  Physical volume "/dev/mapper/mpathae" successfully created
  Physical volume "/dev/mapper/mpathaf" successfully created


[root@servername /]# vgcreate vg11 /dev/

[root@servername /]#  lvcreate -l 100%FREE -n BACKUP vg11


cd /
mkdir BACKUP mount klasörünü oluşturuyoruz


mkfs.xx ile filesystem oluşturuyoruz


[root@servername /]# mkfs.ext4 /dev/vg11/BACKUP
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=8 blocks, Stripe width=8 blocks
335544320 inodes, 2684352512 blocks
134217625 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
81920 block groups
32768 blocks per group, 32768 fragments per group
4096 inodes per group
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
        4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,
        102400000, 214990848, 512000000, 550731776, 644972544, 1934917632,
        2560000000


Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done




Oluşturulan filesystemi mount ediyoruz
[root@servername /]# mount /dev/mapper/vg11-BACKUP /BACKUP/




Boot sonrasında da aktif olması için /etc/fstab dosyasını düzenliyoruz.


[root@servername /]# vi /etc/fstab


#
# /etc/fstab
# Created by anaconda on Tue Jul 11 10:39:36 2017
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#


/dev/mapper/vg11-BACKUP /BACKUP auto defaults 0 0