For enterprises that are heavily reliant on the Web to deliver their products and services, speed and reliability are key to customer satisfaction and retention. Application response times are generally measured in milliseconds or even microseconds. For larger enterprises, creating and maintaining an infrastructure to support a variety of lower latency Web-based applications may be cost prohibitive. For small enterprises, so called Infrastructure-as-a-Service (IaaS) solutions make their businesses possible.
However, as many disgruntled Netflix customers found out on Christmas day, being supported by a big and well-known cloud service provider (CSP), such as Amazon AWS, does not guarantee quality of service – or any service at all. While the details of the outage may be unclear, the event amplifies doubts about CSPs and, at the same time, offers opportunities for smaller more innovative service providers to emerge.
At the December 18, 2012, Wikibon Peer Incite Research Meeting, we learned how ViaWest has differentiated itself in the CSP marketplace. ViaWest has architected and built its own “converged infrastructure” leveraging best-of-breed components including VMware-based vCloud, Cisco UCS servers, 10 gigabit Ethernet switches and several storage solutions including SolidFire high performance SSD which includes a guaranteed quality of service (QoS) for cloud service providers.
According to Matt Wallace, Director of Cloud Architecture for ViaWest, in order to meet and exceed customer expectations for tier 1 application performance, speed and consistency are critical. "QoS at the storage level enables multi-tenancy and lower cost than dedicated servers and traditional hard disk (HDD) storage," he says. "HDD arrays don’t support QoS consistency as Web traffic can be very “bursty” or unpredictable and IO-intensive." ViaWest offers additional “configurable” services including; complex hosting, co-location, and managed services.
CSPs, such as Amazon AWS, are typically less flexible in how an application is supported or hosted and are less able handle bursty, sporadic, random IO traffic – unless the customer is willing to pay an additional premium for more service. As pointed out by Wikibon’s Dave Vellante in his related note, "Eleven Questions to Consider Before Moving Tier One Apps to the Cloud", extensibility, flexibility, network performance, reliability and uptime, security concerns, compliance practices, data governance, response time and latency management are all key considerations for organizations contemplating moving their applications to a CSP. Many CSPs are unable or unwilling to supply an SLA to adequately cover all of these requirements.
Flash and QoS
In contrast to mechanical-based HDD which has moving parts, a semiconductor-based solid state drive (SSD), such as NAND Flash SSD, is much better suited as a storage platform for computation as well as IO. QoS guarantees can eliminate objections from customers when considering Tier 1 apps in multi-tenant environments including Cloud-based applications.
A typical ViaWest SLA includes a QoS guarantee of 1TB of storage and 10k IOPS (IOs per second). ViaWest believes setting a performance expectation upfront by guarantying dedicated storage resources gives it a competitive edge. QoS means guaranteed performance levels, not over-delivering. If Tier 1 apps are going to move to the Cloud, response time variability is potentially problematic, and meaningful QoS guarantees, therefore, essential.
Wallace cites SolidFire as the only all-flash array vendor that he evaluated willing to provide a QoS capability. Other vendors Wallace spoke with told him, “Our arrays are so fast you don’t have to worry about QoS.” That answer wasn’t satisfactory for Wallace.
Action Item: CSPs will need to avoid creating bottlenecks in their infrastructure if they expect to attract and keep tier 1 application clients. While bottlenecks can occur throughout the infrastructure, including in the network fabric and controllers, SSD and flash storage arrays have proven their utility with IO-intensive apps such as Web-based applications and database queries. Therefore, deploying flash will help meet SLAs and eliminate customer objections.
CSPs should also avoid performance degradation and, at the unset of customer relationships, meet performance requirements. This should be accomplished without over-provisioning each customer as, without limiters, applications may execute performance land-grabs.
Flash vendors wanting to establish a footprint in the CSP space will need to add more QoS capabilities to meet performance consistency requirements for multi-tenanted environments and to compete in an evolving marketplace.