#How to add a disk in Nethserver with LVM
We will see how to add a hard drive in an existing Virtual Group.
Version and revision: V1.0 / R3
Skill: General audience.
Published: 2015-09-08
Review: 2015-11-12
Author: Jim
Contact: Nethserver community forum: Jim
At first, I`m strongly recommending to read this LVM Administrator’s Guide:
https://www.centos.org/docs/5/html/Cluster_Logical_Volume_Manager/
There’s all you need to understand what is LVM and how to play safely with it.
In my Microserver Gen8 I have one 160 GB disk in the bay one. This one was configuring like this: ( disk -l output )
Disque /dev/sda: 160.0 Go, 160041885696 octets
255 têtes, 63 secteurs/piste, 19457 cylindres
Unités = cylindres de 16065 * 512 = 8225280 octets
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Identifiant de disque : 0x0002bf10
Périphérique Amorce Début Fin Blocs Id Système
/dev/sda1 * 1 64 512000 83 Linux
La partition 1 ne se termine pas sur une frontière de cylindre.
/dev/sda2 64 19458 155777024 8e Linux LVM
Disque /dev/mapper/vg_microserver-lv_root: 53.7 Go, 53687091200 octets
255 têtes, 63 secteurs/piste, 6527 cylindres
Unités = cylindres de 16065 * 512 = 8225280 octets
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Identifiant de disque : 0x00000000
Disque /dev/mapper/vg_microserver-lv_home: 101.8 Go, 101833506816 octets
255 têtes, 63 secteurs/piste, 12380 cylindres
Unités = cylindres de 16065 * 512 = 8225280 octets
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Identifiant de disque : 0x00000000
Disque /dev/mapper/vg_microserver-lv_swap: 3992 Mo, 3992977408 octets
255 têtes, 63 secteurs/piste, 485 cylindres
Unités = cylindres de 16065 * 512 = 8225280 octets
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Identifiant de disque : 0x00000000
When I went to put one more 1Tb disk in the second bay, I didn`t want to simply add one
partition, but wanted to expend the LVM volume to have flexibility of LVM for futures upgrades.
So when I plugged the 1TB drive, I went to connect in SSH to the server and became root.
did a fdisk -l to ensure the this was well seeing, with the output, I saw a /dev/sdb drive.
So I had create the physical volume:
pvcreate /dev/sdb
When done
pvdisplay
To extend the VolumeGroup, I needed the name of this one, so:
vgdisplay
In this case the VG name is vg_microserver.
So, to extend the actual volume group
vgextend vg_microserver /dev/sdb
To be able to use the new disk space in the volume group, I needed to create a new logical volume in the volume group.
In my case, I want to use all the free space, and the logical volume need a name, it will be tmbackup
lvcreate -l 100%FREE -n tmbackup vg_microserver
here the output of the lvdisplay command
--- Logical volume ---
LV Path /dev/vg_microserver/lv_root
LV Name lv_root
VG Name vg_microserver
LV UUID uw6t0l-RpXQ-dHzo-LmNY-wHBY-NpTE-qA6UT7
LV Write Access read/write
LV Creation host, time nethserver, 2015-07-26 20:21:10 -0300
LV Status available
# open 1
LV Size 50,00 GiB
Current LE 12800
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:0
--- Logical volume ---
LV Path /dev/vg_microserver/lv_home
LV Name lv_home
VG Name vg_microserver
LV UUID QBk1ca-fD7E-DbaG-Yk2O-WD15-2biU-dKfjww
LV Write Access read/write
LV Creation host, time nethserver, 2015-07-26 20:21:30 -0300
LV Status available
# open 1
LV Size 94,84 GiB
Current LE 24279
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:2
--- Logical volume ---
LV Path /dev/vg_microserver/lv_swap
LV Name lv_swap
VG Name vg_microserver
LV UUID 7tAuVa-zzpY-gBnr-nc95-P35Y-gg2f-kSkMfn
LV Write Access read/write
LV Creation host, time nethserver, 2015-07-26 20:22:16 -0300
LV Status available
# open 1
LV Size 3,72 GiB
Current LE 952
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:1
--- Logical volume ---
LV Path /dev/vg_microserver/lv_tmbackup
LV Name lv_tmbackup
VG Name vg_microserver
LV UUID lyioV1-8q8e-sTDz-mxpv-tBrD-M5Eb-h8WKRR
LV Write Access read/write
LV Creation host, time nethserver, 2015-08-04 21:07:20 -0300
LV Status available
# open 1
LV Size 931,51 GiB
Current LE 238467
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:3
When all was done, i need to create the ext4 partition in this new volume:
mkfs.ext4 /dev/vg_microserver/lv_tmbackup
Finally, I mounted the partition in /home/tmbackup
mount -t ext4 /dev/mapper/vg_microserver-lv_tmbackup /home/tmbackup
I adjusted the /etc/fstab to automatically mount the partition at startup
/dev/mapper/vg_microserver-lv_root / ext4 defaults 1 1
UUID=6409d507-3801-4089-b451-4d671026c268 /boot ext4 defaults 1 2
/dev/mapper/vg_microserver-lv_home /home ext4 defaults 1 2
/dev/mapper/vg_microserver-lv_swap swap swap defaults 0 0
/dev/mapper/vg_microserver-lv_tmbackup /home/tmbackup ext4 defaults 1 2
tmpfs /dev/shm tmpfs defaults 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
sysfs /sys sysfs defaults 0 0
proc /proc proc defaults 0 0
That’s all ! 
