Shared block storage

In some instances, a persistent disk that is shared among several VMs is required to provide a platform for distributed file systems (OCFS2, GPFS, Oracle ASM, etc.) or other clustered services. This can be achieved within HyperCloud by modifying the Attributes of a generic datablock that will allow its use between two or more Virtual Machines.

From the HyperCloud GUI, navigate to the Create Image Wizard where a Name and Description can be given to the disk. Set the Type to Generic storage datablock and set the Image to persistent and Empty disk image

Expand the Advanced Options and input the attribute PERSISTENT_TYPE with the value of SHAREABLE, click the blue circled + button at the bottom of the field.

After setting all the Image fields, finalize the creation by pressing the green Create button.

With the Image created, it can now be attached to the VMs or used as a disk when creating a VM Template.

When attaching to a VM or applying as a disk, it is important to set the cache equal to none.

With the disk added to the VM Template, several copies of the VM can be instantiated and all will share the persistent block storage.

Navigating back to the Image list under the Storage menu, select the shared datablock and click VMs to show the list of VMs that the disk has been attached.

Data can now be saved to the disk and accessed by all the VMs.