Quality of Service (QoS)
There is plenty of talk about QoS, but rarely is it clearly defined. In the past, storage systems set minimum and maximum IOPS at the volume level, which means the dozens of very different VMs inside get the same level of QoS.
VM-level QoS allows IT managers to set specific parameters for each VM — simply toggle the minimum and maximum IOPS as desired, to impose a ceiling on a rogue VM or ensure resources for a mission-critical VM (e.g., a finance server at end of month). VM-level QoS can also be used to create multiple tiers of service on a single platform. In the past, enterprises and service providers typically bought multiple storage devices, with some dedicated to "gold" applications, others to "silver" applications and so on. The array itself was the dividing line. With VM-level QoS, you can establish gold, silver, bronze and/or other tiers on one storage device, and then assign each VM to a tier.
Essential Elements in Building an Agile Data Center
Essential Elements in Building an Agile Data Center
Today, about 75 percent of all workloads in data centers are virtualized and this number is only expected to grow. The biggest challenge IT admins face is that conventional storage is ill-equipped to deal with virtualization because the storage is built for physical workloads.
Problems arise as legacy storage, with logical unit numbers (LUNs) and volumes that might house tens or hundreds of individual virtual machines (VMs), causes resident VMs to fight over limited resources. This is a phenomenon called the "noisy neighbor." While one common solution is to throw more high-performance flash storage at the problem, this alone cannot fix the problem. It simply postpones dealing with the underlying problem (LUNs). Costs can spiral out of control as an all-flash storage architecture dedicated to LUNs and volumes does not necessarily overcome the pain points of managing virtual workloads.
While many companies aspire to build cloud-scale infrastructures with agility and automation for diverse virtualized workloads, they have been forced to choose between limited scale-out that requires a large number of disks or expensive and inefficient scale-out. According to Chuck Dubuque, senior director of product and solution marketing for Tintri, five key areas that are critical for successful data center modernization efforts include speed, quality of service (QoS), disaster recovery, predictive data analytics, and manageability at scale.
