Parallax

Abstract

Parallax is a distributed storage system that uses virtualization to provide storage facilities specifically for virtual environments. The system employs a novel architecture in which storage features that have traditionally been implemented directly on high-end storage arrays and switches are relocated into a federation of storage VMs, sharing the same physical hosts as the VMs that they serve. This architecture retains the single administrative domain and OS agnosticism achieved by array- and switch-based approaches, while lowering the bar on hardware requirements and facilitating the development of new features. Parallax offers a comprehensive set of storage features including frequent, low-overhead snapshot of virtual disks, the 'gold-mastering' of template images, and the ability to use local disks as a persistent cache to dampen burst demand on networked storage.

Towards Transparent Throughput Elasticity for IaaS Cloud Storage

“…All write operations are sent to the HDD in order to avoid degrading the performance of the flash storage. Using a fast device to cache both reads and writes from a read-only virtual disk snapshot is possible by using copy-on-write and/or mirroring (QCOW2, n.d.; Meyer et al, 2008;Nicolae, Bresnahan, Keahey, & Antoniu, 2011). However, one of the disadvantages in this context is fragmentation, for which specialized strategies might be necessary (Nicolae & Cappello, 2013).…”