IO Virtualization Technology Overview

The Atlantis Approach to IO Virtualization

Atlantis ILIO is an IO virtualization technology for VDI that front ends a traditional SAN/NAS storage system to enable high performance IO, storage optimization/consolidation and virtual desktop image composition.

Extracting IO state and creating Flocks™

Flocks (File and Block IO) are Atlantis Computing patent pending format of virtualized data storage that merges file and block data into a component. Flocks are block devices with semantic knowledge of their contents. Flocks are aggregated and composited to form dynamic volumes that host NTFS and Unix filesystems. The benefit of storing data in flocks is that a common set of OS and application components can be used to create desktops and servers that are fully customizable (including allowing users to install applications) yet allow the underlying common OS and applications to be centrally changed (without the limitations suffered by traditional block based Copy on Write approaches like linked clones) or resource intensive instance-based file system based copy on write and kernel installed read write redirection approaches which do not guarantee application compatibility.

Real time In-line De-duplication of Storage Objects

Traditional de-duplication is applied to a volume after duplicated data has been committed to it. Traditional de-duplication processes a volume by calculating a unique check sum for each block of data based on its contents and then sharing references to a single block wherever blocks have the same checksum. De-duplication has been used with virtualization as a means to reduce the physical storage requirements for virtual machine images where the image content is highly repetitious. ILIO real time de-duplication works by marking and identifying duplicate objects as they are virtualized into flocks before data is committed to the storage volume. As a result the de-duplication process is more efficient and processes data in real time rather than as a post process. In practice this means that if two users on a VDI desktop pool install the same application, only one physical copy of the application is stored.

Using a single common image of operating system and applications

ILIO allows the use of a single common physical copy of an operating system or application to be used across all virtual desktops instances. In practice this means that in a 10,000 instance Virtual Desktop implementation, there is just one copy of the OS and applications and all the 10,000 instances share the same base image. This typically results in a 20x storage reduction.

Caching Frequently used IO's and Offloading the Backend SAN/NAS

Latency between SAN/NAS storage and VDI servers is a critical parameter in determining overall performance for a VDI deployment. As discussed previously, VDI is IO intensive and needs low latencies coupled with large throughput to work well. On loaded SAN/NAS systems latencies increase into the 10s of milliseconds and this can have negative consequences on user experience in the case of virtual desktops. ILIO allows frequently accessed and common IO to be cached close to the server. This serves two important purposes:

SAN/NAS Offload

ILIO can offload up to 95% of the IO on homogenous image deployment (as is the case with VDI where most OS and application components are shared). This means that a SAN/NAS system is no longer overwhelmed by many desktops making IO requests.

IO Acceleration

Atlantis ILIO allows important classes of IO such as Operating system virtual memory page files and application swap files to be served from cache thus dramatically improving the performance of IO intensive virtual workloads like virtual desktops.