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A method and system for an allocation aware file system

IP.com Disclosure Number: IPCOM000237332D
Publication Date: 2014-Jun-13
Document File: 4 page(s) / 95K

Publishing Venue

The IP.com Prior Art Database

Abstract

This publication discloses a filesystem that allows to selectively mark a set of files or directories to be physically located on a specific portion of the backed disk device so that it can be in turn mapped to a specific physical disk through the device mapper facility.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 45% of the total text.

Page 01 of 4

A method and system for an allocation aware file system

Applications installed in a typical enterprise operating system may have different sets of requirements in terms of file system capabilities. There are some files that have to be accessed very fast; others that need to be encrypted in a very secure way, for example leveraging the hardware-level encryption provided by some disks, and so on.

Some typical solutions to tackle such problems is to use different disks and have different portions of the file system mounted under different physical disks. Files having specific I/O requirements got located under those locations of the file system mounted on the fasted disks. Files requiring encryption are located under a different sub-tree of the file system mounted under a disk providing hardware-level encryption.

More sophisticated configurations could also be achieved through the device-mapper capabilities available on most operating systems. These above mechanisms rely upon the fact that the file system of the machine is appropriately partitioned into specific sub trees so that each of them could be mounted or assigned to a specific physical disk.

Such kind of approaches does not cover the cases where only a subset of the files of an application requires a fast access or the fact that more than one application exists on the machine whose files have to be accessed with high I/O performances or in general with special requirements.

The core idea presented here is based upon an "allocation aware file system" (AAFS) coupled with a device mapper configuration; this allows to selectively mark a set of files or directories to be physically located on a specific portion of the backed disk device so that it can be in turn mapped to a specific physical disk through the device mapper facility.

The AAFS allows to partition the entire device into one or more zones, each having a well defined size and an ID that uniquely identifies it. Then each file and/or directory of the file system may have a new metadata associated to it that is used to specify the zone of the device where that file (or the files contained under a given directory) has to be physically written. The AAFS, based on that metadata, will ensure that the bytes of a given file are written into the portion of the device identified that that zone ID.

Given such infrastructure it is then possible, through the Device Mapper facility, to map in turn, each zone of the device into separate physical disks, potentially having different I/O performances or other specific features, such as hardware-level encryption. This capability could then be exploited by operating system services or by specific applications for distributing they data on different disk zones to fit specific needs.

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Page 02 of 4

The picture below depicts how the system is going to work. On the upper part a sample representation of the files/directories in a typical file system is shown. Some of the files/directories have...