Coordinated hypervisor staging of I/O data for storage devices on external cache devices

摘要

A management technique for input/output operations (JO) leverages a hypervisor's position as an intermediary between virtual machines (VMs) and storage devices servicing the VMs to facilitate improvements in overall I/O performance for the VMs. According to this new I/O management technique, the hypervisor sends write requests from VMs destined for storage devices to an I/O staging device that provides higher I/O performance than the storage devices, for caching in the I/O staging device in a write-back mode. Once the I/O staging device has received and acknowledged the write request, the hypervisor immediately provides an acknowledgement to the requesting VM. Later on and asynchronously with respect to the write requests from the VMs, the hypervisor reads the write data from the I/O staging device and sends it over to the storage devices for storage therein.

主权项

1. A computer system having a plurality of host computers, each having one or more virtual machines (VMs) running therein and system software that supports the VMs, the computer system comprising:
a first shared storage device connected to each of the host computers; and a second shared storage device that has a larger capacity and higher input/output latency than the first shared storage device, wherein the system software of each host computer is configured to cache data that are to be written in the second shared storage device in the first shared storage device in a write-back mode, and wherein the system software of each host computer is configured to copy the data cached thereby in the first shared storage device to the second shared storage device at a first rate, the first rate being based on a plurality of moving average rates, each of which is a moving average rate at which the system software of a corresponding one of the plurality of host computers has cached data in the first shared storage device.