News Column

Patent Issued for Methods and Systems for Defragmenting Virtual Machine Prefetch Data on Physical Storage

July 22, 2014



By a News Reporter-Staff News Editor at Journal of Technology -- Symantec Corporation (Mountain View, CA) has been issued patent number 8775716, according to news reporting originating out of Alexandria, Virginia, by VerticalNews editors.

The patent's inventors are Cook, Randall R. (Springville, UT); Hernacki, Brian (San Carlos, CA); Satish, Sourabh (Fremont, CA); Sobel, William E. (Jamul, CA).

This patent was filed on November 8, 2012 and was published online on July 8, 2014.

From the background information supplied by the inventors, news correspondents obtained the following quote: "Users may experience startup delays when a computing system or application starts up because of the data and software modules that the system or application must load from physical storage to memory. The data and code accessed during a system or application startup may be referred to as prefetch data. As computing systems and applications become larger and more complex, the size of prefetch data may grow and may cause startup delays to increase.

"To reduce startup delays, some systems and applications may use prefetchers. For example, an operating system may use a prefetcher that monitors code and data accessed during a boot process. The prefetcher may store the information collected during the boot process in a trace file. Subsequent boots of the operating system may use the trace file to load code and data more efficiently. Similarly, applications may use prefetchers that monitor code and data accessed during application startup, and trace files created by an application prefetcher may be used to start the application more efficiently in the future.

"Some prefetch technologies may attempt to improve boot or startup times by optimizing organization of prefetch data on physical storage. For example, a system may use a trace file to defragment prefetch data. Some systems and applications may also use trace files to physically organize prefetch data in the order in which it is accessed during startup. By optimizing organization of the prefetch data on physical storage, systems may decrease access time for the prefetch data, which may reduce startup delays.

"Unfortunately, traditional prefetch technologies may not reduce startup delays in virtual machines. A virtual machine runs on a host machine. The host machine may interface with the virtual machine by providing the virtual machine with emulated hardware, such as a virtual disk. The host may implement a virtual disk as a file on the host's physical storage device, and the host may distribute this virtual disk file arbitrarily on the host's physical storage device. The virtual disk file may be stored in one part or in segments, contiguously or non-contiguously, ordered or unordered, with various segments of the virtual disk file on physically disparate portions of the host's physical storage device.

"When a virtual machine employs a prefetch technology that optimizes prefetch data organization, prefetch data may be placed in optimal locations on the virtual disk. However, because the virtual disk file may be distributed arbitrarily across the host's physical storage device, optimally reorganizing prefetch data relative to the virtual disk results in arbitrary, rather than optimal, reorganization of the prefetch data on the host's physical storage device. Because the prefetch data is arbitrarily reorganized on the host's physical storage device, startup time may not decrease and could even increase."

Supplementing the background information on this patent, VerticalNews reporters also obtained the inventors' summary information for this patent: "Embodiments of the instant disclosure are directed to decreasing system and application startup times on a virtual machine. Some embodiments may decrease startup time by defragmenting virtual machine prefetch data on a physical storage device. For example, a defragmenting module may defragment physical storage of a virtual machine by 1) obtaining prefetch information associated with prefetch data of the virtual machine and 2) defragmenting, based on the prefetch information, the prefetch data on a physical storage device.

"Prefetch information may include any information that enables a defragmenting module to decrease system or application startup time by reorganizing the prefetch data on the physical storage device. In one example, prefetch information may include the starting location of the prefetch data on the virtual disk, the length of the prefetch data on the virtual disk, and/or a geometry specification that specifies how the virtual disk maps to the physical storage device. Prefetch information may also include a trace file created by monitoring a virtual machine's boot process.

"As previously mentioned, one step in defragmenting physical storage of a virtual machine may be obtaining prefetch information for the virtual machine. A defragmenting module may obtain prefetch information by receiving the prefetch information from the virtual machine or by mounting and reading a file system of the virtual machine to identify prefetch information. For example, the defragmenting module may search a virtual machine for a trace file that identifies prefetch data of the virtual machine. In some embodiments, a defragmenting module may obtain prefetch information by monitoring data and code that the virtual machine or an application on the virtual machine accesses during startup.

"After obtaining the prefetch information, the defragmenting module may use the prefetch information to defragment the prefetch data. The defragmenting module may defragment the prefetch data by placing the prefetch data on a fast-access segment of the physical storage device, by placing the prefetch data contiguously on the physical storage device, and/or by ordering the prefetch data on the physical storage device. In one example, the physical storage device may be a hard disk. The defragmenting module may defragment the prefetch data by placing the prefetch data contiguously on the outside of the hard disk and by ordering the prefetch data in the order in which the data is accessed at system or application startup.

"Features from any of the above-mentioned embodiments may be used in combination with one another in accordance with the general principles described herein. These and other embodiments, features, and advantages will be more fully understood upon reading the following detailed description in conjunction with the accompanying drawings and claims."

For the URL and additional information on this patent, see: Cook, Randall R.; Hernacki, Brian; Satish, Sourabh; Sobel, William E.. Methods and Systems for Defragmenting Virtual Machine Prefetch Data on Physical Storage. U.S. Patent Number 8775716, filed November 8, 2012, and published online on July 8, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8775716.PN.&OS=PN/8775716RS=PN/8775716

Keywords for this news article include: Technology, Symantec Corporation.

Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2014, NewsRx LLC


For more stories covering the world of technology, please see HispanicBusiness' Tech Channel



Source: Journal of Technology


Story Tools






HispanicBusiness.com Facebook Linkedin Twitter RSS Feed Email Alerts & Newsletters