OpenStack Part 6.5: Adding disks

As announced in the previous post, I bought 4 used disks from eBay and inserted them into the machine. This is the synopsis of creating a RAID5 volume, put it into an LVM volume group, and assign that VG to libvirt. Libvirt can then create logical volumes in that VG, and attach them the virtual machines.

A Debian configuration guide I followed:
https://debian-handbook.info/browse/stable/advanced-administration.html#sect.raid-and-lvm

Checking the presence of the new SATA disks in the system:
root@PANICLOUD:/home/nicky# lsblk
NAME                            MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT
fd0                               2:0    1     4K  0 disk
sda                               8:0    0 232.9G  0 disk
└─sda1                            8:1    0 232.9G  0 part
└─md0                           9:0    0 465.5G  0 raid0
├─md0p1                     259:0    0 243.1M  0 md    /boot
├─md0p2                     259:1    0     1K  0 md
└─md0p5                     259:2    0 465.3G  0 md
├─PANICLOUD--vg-root      253:0    0   9.3G  0 lvm   /
├─PANICLOUD--vg-swap_1    253:1    0  18.1G  0 lvm   [SWAP]
├─PANICLOUD--vg-home      253:2    0   100G  0 lvm   /home
├─PANICLOUD--vg-images    253:3    0   100G  0 lvm   /opt/images
└─PANICLOUD--vg-instances 253:4    0   100G  0 lvm   /opt/instances
sdb                               8:16   0 232.9G  0 disk
└─sdb1                            8:17   0 232.9G  0 part
└─md0                           9:0    0 465.5G  0 raid0
├─md0p1                     259:0    0 243.1M  0 md    /boot
├─md0p2                     259:1    0     1K  0 md
└─md0p5                     259:2    0 465.3G  0 md
├─PANICLOUD--vg-root      253:0    0   9.3G  0 lvm   /
├─PANICLOUD--vg-swap_1    253:1    0  18.1G  0 lvm   [SWAP]
├─PANICLOUD--vg-home      253:2    0   100G  0 lvm   /home
├─PANICLOUD--vg-images    253:3    0   100G  0 lvm   /opt/images
└─PANICLOUD--vg-instances 253:4    0   100G  0 lvm   /opt/instances
sdg                               8:96   0 931.5G  0 disk
sdh                               8:112  0 931.5G  0 disk
sdi                               8:128  0 931.5G  0 disk
sdj                               8:144  0 931.5G  0 disk

 

Creating the RAID5 volume:
root@PANICLOUD:/home/nicky# mdadm --create /dev/md1 --level=5 --raid-devices=4 /dev/sdg /dev/sdh /dev/sdi /dev/sdj

Creating the LVM phyiscal volume:
root@PANICLOUD:/home/nicky# pvcreate /dev/md1
Physical volume "/dev/md1" successfully created
root@PANICLOUD:/home/nicky# pvdisplay
--- Physical volume ---
PV Name               /dev/md0p5
VG Name               PANICLOUD-vg
PV Size               465.28 GiB / not usable 2.02 MiB
Allocatable           yes
PE Size               4.00 MiB
Total PE              119110
Free PE               35298
Allocated PE          83812
PV UUID               UdCEwD-mlv1-EuIw-L0jc-lrgK-QGjX-RM1AdD

“/dev/md1” is a new physical volume of “2.73 TiB”
— NEW Physical volume —
PV Name               /dev/md1
VG Name
PV Size               2.73 TiB
Allocatable           NO
PE Size               0
Total PE              0
Free PE               0
Allocated PE          0
PV UUID               FRsRMz-6HNs-S6d6-QXOw-beOf-DbB8-MGuLu1

Creating the volume group:
root@PANICLOUD:/home/nicky# vgcreate PANICLOUD_STORAGE-vg /dev/md1
Volume group "PANICLOUD_STORAGE-vg" successfully created
root@PANICLOUD:/home/nicky# vgdisplay
--- Volume group ---
VG Name               PANICLOUD-vg
System ID
Format                lvm2
Metadata Areas        1
Metadata Sequence No  9
VG Access             read/write
VG Status             resizable
MAX LV                0
Cur LV                5
Open LV               5
Max PV                0
Cur PV                1
Act PV                1
VG Size               465.27 GiB
PE Size               4.00 MiB
Total PE              119110
Alloc PE / Size       83812 / 327.39 GiB
Free  PE / Size       35298 / 137.88 GiB
VG UUID               nWgVHx-Xuq9-AGAh-iI6g-4DoR-HcIn-Nq1WhR

— Volume group —
VG Name               PANICLOUD_STORAGE-vg
System ID
Format                lvm2
Metadata Areas        1
Metadata Sequence No  1
VG Access             read/write
VG Status             resizable
MAX LV                0
Cur LV                0
Open LV               0
Max PV                0
Cur PV                1
Act PV                1
VG Size               2.73 TiB
PE Size               4.00 MiB
Total PE              715305
Alloc PE / Size       0 / 0
Free  PE / Size       715305 / 2.73 TiB
VG UUID               AmZ7Yx-4p37-ZgLy-wIvC-1pOU-wdwP-JK64m1

Make sure that afterwards you run “updateinitramfs -u” so that the RAID array is assembled again after a reboot of the machine.

This guide summarizes the process to assign the volume group to libvirt with virt-manager.

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