This talk presents Synnefo's evolution since FOSDEM '13, focusing on its integration with Ganeti, Archipelago, and Ceph to deliver a unified, scalable storage substrate for IaaS clouds. The talk will begin with an overview of the Synnefo architecture (Python, Django, Ganeti, and Xen or KVM). Then, it will introduce Archipelago, a software-defined, distributed storage layer that decouples Volume and File operations/logic from the underlying storage technology, used to store the actual data. Archipelago provides a unified way to provision, handle and present Files, Images, Volumes and Snapshots independently of the storage backend. We will focus on using Ceph/RADOS as a backend for Archipelago. With Archipelago and its integration with Synnefo and Ganeti one can: * maintain commonly-used data sets as snapshots and attach them as read-only disks or writeable clones in VMs running the application, * begin with a base OS image, bundle all application and supporting library code inside it, and upload it to the Archipelago backend in a syncing, Dropbox-like manner, * start a parallel HPC application in hundreds of VMs, thinly provisioned from this Image, * modify the I/O processing pipeline to enable aggressive client-side caching for improved number of IOPS, * create point-in-time snapshots of running VM disks, * share snapshots with other users, with fine-grained Access Control Lists, * and sync them back to their PC for further processing. The talk will include a live demonstration of a workflow including this functionality in the context of a large-scale public cloud. The intended audience spans from enterprise users comparing cloud platforms, to developers who wish to discover a different design approach to IaaS clouds and storage virtualization. Please see the abstract above for a rough sketch of the proposed presentation. The presentation will mostly consist of live demonstration and a small deck of slides, meant to describe the main features of Archipelago and its integration with Synnefo, as well as provoke discussion in the Q&A session. The main workflow in the demonstration will be [copied and pasted from the Abstract]: * begin with a base OS image, bundle all application and supporting library code inside it, and upload it to the Archipelago backend in a syncing, Dropbox-like manner, * start a parallel HPC application in hundreds of VMs, thinly provisioned from this Image, * modify the I/O processing pipeline to enable aggressive client-side caching for improved number of IOPS, * create point-in-time snapshots of running VM disks, * share snapshots with other users, with fine-grained Access Control Lists, * and sync them back to their PC for further processing