Network LVM-storage

This is the documentation for the deprecated product VMmanager 5. It is no longer updated and may be irrelevant. Documentation for the current version of VMmanager can be found in the VMmanager 6 section.

The virtual disk of a virtual machine is the HDD image. Virtual disks are stored in a local or network storage. A network LVM-storage is similar to a common lvm except for some details. However, the physical volume where a group of volumes is located is a network device.

This article describes how to configure the network LVM-storage. For more information please refer to the article Network storages.

Peculiarities

When creating a virtual machine, on the same cluster node a virtual disk is created, and it will be accessible on all the cluster node. It will be active only on one node.

When migrating a virtual machine, the virtual disk will not copy but will activate on the target node. On the source node, the disk will be disabled.

Example of configuration using open-iscsi

Network storage configuration

Install iSCSI:
```
# yum install scsi-target-utils
```

Configure lvm:

# pvcreate /dev/sda2
  Physical volume "/dev/sda2" successfully created
# vgcreate vg0 /dev/sda2
  Volume group "vg0" successfully created

Configure the tgtd configuration file:

# cat /etc/tgt/targets.conf

...
<target iqn.2014-04.net.ispsystem.nlvm:storage.nlvm>
    backing-store /dev/sda2
    initiator-address 10.1.1.1 #cluster node IP address
    initiator-address 10.1.1.2
    initiator-address 10.1.1.3
</target>
...

Restart tgtd:

# service tgtd restart
  Stopping SCSI target daemon: [ OK ]
  Starting SCSI target daemon: [ OK ]

Add iptables rules, if needed:

iptables -I INPUT 1 -p tcp --dport 3260 -j ACCEPT
service iptables save

Connecting to cluster nodes

Connect the disk on each cluster node

iscsiadm -m discovery -t st -p 10.1.2.1
iscsiadm -m node --login -p 10.1.2.1

Once completed you can add a "network LVM" storage named vg0 into VMmanager.