In August, 2012 I wrote an article discussing storage technologies from multiple vendors and their fit for VDI workloads. The original article may be found here. In the first article I covered Atlantis Computing ILIO, EMC VNX Series, Nexenta, Nimble Storage, Nutanix and Whiptail.
I also commented about other storage technologies that may change the way VDI is being deployed today. For more information read VDI Architectures using Storage Class Memory.
In this second part I am covering storage vendors, Violin Memory and Tintri.
Violin Memory storage arrays are is an enterprise-class all-flash-based memory array that deliver performance density (highest IOPS/TB) to address the demanding VDI workload requirements. The array provides provides high availability and reliability. Here are some technical facts:
The architecture consists of four custom-built flash controllers mapped to a switched memory architecture that delivers a completely non-blocking read and write operation, or any mix of the two. The incoming IOs are striped using a patented flash management methodology across these controllers resulting in optimized and predictable performance. System-wide flash erase management is performed using a Violin proprietary ‘heat map’ technology in the background so that it does not impact the IOs.
According to Violin this mechanism delivers sustained IOPs and low latency for even random IO to significantly reduce the boot times and application access times even at large number of virtual desktops. This is something that is difficult to impossible to achieve with flash solutions built using off the shelf flash controllers and SSD components.
A single system fits in 3U of rack space and can deliver one million IOPS with 4GB/sec of bandwidth to host few thousands of virtual desktops in a single Violin 6000 series storage array.
Enterprise Class reliability – System-wide wide striping, several levels of error handling/correction increase overall life of the flash media. The system is built with a fully redundant architecture, with no single point of failure. The systems also supports non-disruptive upgrades that eliminate any need for planned downtime.
Flexibility and ease of use – The products come with a wide variety of network connectivity options with 8-ports of Fibre Channel, 10GE (iSCSI), Infiniband or direct attached PCIe connectivity. The product also offers flexible management options using web GUI, CLI and a complete set of REST APIs.
I have never used Violin, therefore I am not able to technically comment on it. However, I did meet with couple sales folks from Violin. Violin Memory array is no doubt in a category where it should be able to hold almost any workload type. 1 Million IOPS under microsecond latency is not for every vendor. I know they have a very stable solution, but they also face appalling competition from other Flash based arrays, and that include those that implement inline block de-duplication. In the VDI context, if Linked Clones is the solution in use, it’s arguable that in-line block de-duplication doesn’t bring many benefits. However, I mentioned in the past how we believe VMware Mirage and Full-Clones will change the VDI spectrum. Violin doe not support VAAI today.
Tintri VMstore is a storage appliance that is purpose-built for virtual environments. Tintri’s custom file system is designed to monitor, allocate resources, enable features, and set policies at the per-VM or per-vDisk level rather than per-LUN, volume, tier, RAID group or other traditional storage object. According to Tintri this provides a simpler, more intuitive management process.
The solution provides per-VM quality of service within a datastore allowing storage and virtual administrators to mix virtual desktops and virtual servers within the same datastore.
Each physical VMstore provides an interchangeable “datastore” (a logical rather than physical concept). One logical datastore per one physical VMstore node – just like one physical server provides you with one logical “host”. A host provides the CPU, memory and networking resources for your VMs, while a datastore provides them with persistent storage.
VMstore uses a hybrid flash/disk architecture that provides both virtual desktops alike the right level of resources, when and where they need it, to ensure continuous quality of service.
Key features include:
Cloning and Snapshotting: Array side cloning and snapshots from the same base image help with overall performance and capacity with VDI.
Predictable VM performance: VMstore’s file system delivers performance for each VM out of flash without manual configuration or VM placement.
Inline de-duplication, data compression, and working-set analysis: Tintri provides data inline de-duplication and compression as it arrives. This greatly reduces the cost of flash performance. All applications (including virtual desktop applications) have a significant amount of “cold” or infrequently accessed blocks. Tintri’s working-set analysis allows infrequently accessed 8 KB blocks to be “paged back” to hard disk drives rather than wasting space in flash storage.
Instant performance bottleneck visualization: Real-time VM and vDisk-level insight on IO, throughput, end-to-end latency and other key metrics enables rapid VDI performance diagnosis.
According to Tintri 99% of IO is delivered from flash. All writes are committed to flash, and 99% or more of reads are from flash. Yet they say that having just a single datastore, and no LUNs or other storage abstractions with different performance characteristics, eliminates storage configuration and management issues. Tintri VMstore’s ability to allocate resources for a particular VM ensures quality of service at the proper time and in the proper place, which results in dramatically less overprovisioning and lower costs.
I have never used Tintri, therefore I am not able to technically comment on it. I place Tintri on the innovators category, such as Nutanix and Atlantis Diskless. They have re-invented storage infrastructure for virtualized environments. Their product has got some good attention and love from well known virtualization bloggers. The ability to do in-line de-duplication and yet not be an all-flash storage array in very interesting. I hope this also means their TCO and acquisition costs are lower than competitors with similar technology and all based flash arrays. For VMware View environment using CBRC Tintri’s ability to move data to Flash is not something that will provide lots of benefits, however when it comes to write IOs the ability to stage on Flash will definitely help with end-user performance. Tintri support all VAAI primitives.
Soon, I expect to get my hands on Nimble Storage and NimbleData appliance and be able to share my experiences here.