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Nonvolatile Memory with Service Port for Accelerated File System Processing in an On-Demand Environment

IP.com Disclosure Number: IPCOM000124719D
Original Publication Date: 2005-May-04
Included in the Prior Art Database: 2005-May-04
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Abstract

Nonvolatile memory (like battery buffered SRAM, NVRAM) is used to accelerate file systems. Because consistency would normally require a certain sequence of write requests to a disk, operations like creating a file can take long without the use of nonvolatile memory. The acceleration consists in writing the informations to the NVRAM immediately and to the disk later. If the system crashes before the information has been written to disk the content of the NVRAM (which is assumed to survive a crash) can be used to complete the interrupted operation and to bring in this way the disk to a consistent state again. However, when the disk is removed from the system during the crash the restoration is not possible anymore.

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Nonvolatile Memory with Service Port for Accelerated File System Processing in an On-Demand Environment

It is proposed to add an interface to the NVRAM used for filesystem acceleration which allows reading out the NVRAM when the system is switched off or unaccessible due to other problems. The information from the NVRAM can then be transported together with the disk it belongs to. Therefore, the disk can be brought into a consistent state in the new system.

This is important for the On-demand Era, because systems are rearranged to meet new requirements.

Example: A server with two disk stations (e.g. IBM Enterprise Storage Server) is used, and one customer requires more processing capabilities. Therefore, one of the disk stations is connected to a new server, retaining the customers data. However, the information from the NVRAM in Server A is needed in the new server to bring the disk station into a consistent state again. Furthermore, this is a service related feature, because it eases analysis of problems and recreation of data of a customer. Without the invention the customer would need a new server temporarily to avoid the danger of loosing the data in the server's NVRAM. With the decreasing prices of nonvolatile memory (magnetic RAM) the handling of nonvolatile memory in servers will get more importance, possibly beyond file system acceleration.

Currently, the USB (Universal serial bus) is the most convenient standard for the proposed purpose. It is found on every notebook and there are memory devices ("USB memory stick") widely available. Furthermore it provides sufficient bandwidth for the described pr...