Cloned from launchpad blueprint https://blueprints.launchpad.net/cinder/+spec/shared-volume.

Description:

Provide the ability to attach a single volume to multiple instances simultaneously.  In order to do this R/W there are a number of issues involved with respect to data corruption etc.  As a first pass it would be very useful to introduce a Read Only option that could be specified during attach and used to allow simultaneous attach to multiple instances.

Most of this will require work in Nova/Compute but there will need to be some comprehension added to Cinder, and perhaps the ability to mark a volume as Read Only might be useful as well.

This R/O volumes could be especially useful for things like Images and even D2D backups.  

There's also a need for FC environments to multi-attach in general.

Specification URL (additional information):

None