公开(公告)号：WO2002029572A3

公开(公告)日：2002-04-11

申请号：PCT/US2001/031422

申请日：2001-10-04

Applicant: NETWORK APPLIANCE, INC.

Inventor： VISWANATHAN, Srinivasan ,  KLEIMAN, Steven, R.

IPC: G06F11/20

Abstract: The invention provides a method and system for recovery of file system data in file servers having mirrored file system volumes. The invention makes use of a "snapshot" feature of a robust file system (the "WAFL File System) to rapidly determine which of two or more mirrored volumes is most up-to-date, and which file blocks of the most recent mirrored volume have been changed from each one of the mirrored file systems. In a preferred embodiment, among a plurality of mirrored volumes, the invention rapidly determines which is the most up-to-date by examining a consistency point number maintained by the WAFL File System at each mirrored volume. The invention rapidly pairwise determines what blocks are shared between that most up-to-date mirrored volume and each other mirrored volume, in response to a snapshot of the file system maintained at each mirrored volume and are stored in common pairwise between each mirrored volume and the most up-to-date mirrored volume. The invention re synchronizes only those blocks that have been changed between the common snapshot and the most up-to-date snapshot.

公开(公告)号：WO2003009286A2

公开(公告)日：2003-01-30

申请号：PCT/US2001/051321

申请日：2001-10-25

Applicant: NETWORK APPLIANCE, INC.

Inventor： KAHN, Andy ,  SUNDARAM, Rajesh ,  VISWANATHAN, Srinivasan ,  KLEIMAN, Steven, R.

IPC: G11B20/00

CPC classification number: G06F11/1076 ,  G11B20/18 ,  H03M13/096

Abstract: A method and apparatus for a reliable data storage system using block level checksums appended to data blocks. Files are stored on hard disks in storage blocks, including data blocks and block-appended checksums. The block-appended checksum includes a checksum of the data block, a VBN, a DBN, and an embedded checksum for checking the integrity of the block-appended checksum itself. A file system includes file blocks with associated block-appended checksum to the data blocks. The file blocks with block-appended checksums are written to storage blocks. In a preferred embodiment a collection of disk drives are formatted with 520 bytes of data per sector. For each 4,096-byte file block, a corresponding 64-byte block-appended checksum is appended to the file block with the first 7 sectors including most of the file block data while the 8th sector includes the remaining file block data and the 64-byte block-appended checksum.

Abstract translation: 用于使用附加到数据块的块级校验和的可靠数据存储系统的方法和设备。 文件存储在硬盘上的存储块中，包括数据块和块附加校验和。 附加块的校验和包括数据块的校验和，VBN，DBN和嵌入校验和，用于检查块附加校验和本身的完整性。 一个文件系统包括文件块，并在数据块中附加了与块相关的校验和。 带块添加校验和的文件块被写入存储块。 在一个优选实施例中，磁盘驱动器的集合被格式化为每个扇区520个字节的数据。 对于每个4,096字节的文件块，相应的64字节的块附加校验和被附加到文件块，前7个扇区包括大部分文件块数据，而第8个扇区包括剩余的文件块数据和64字节 块添加校验和。

公开(公告)号：EP1364368A2

公开(公告)日：2003-11-26

申请号：EP01274308.4

申请日：2001-10-25

Applicant: Network Appliance, Inc.

Inventor： KAHN, Andy ,  SUNDARAM, Rajesh ,  VISWANATHAN, Srinivasan ,  KLEIMAN, Steven, R.

IPC: G11B20/00

CPC classification number: G06F11/1076 ,  G11B20/18 ,  H03M13/096

Abstract: A method and apparatus for a reliable data storage system using block level checksums appended to data blocks. Files are stored on hard disks in storage blocks, including data blocks and block-appended checksums. The block-appended checksum includes a checksum of the data block, a VBN, a DBN, and an embedded checksum for checking the integrity of the block-appended checksum itself. A file system includes file blocks with associated block-appended checksum to the data blocks. The file blocks with block-appended checksums are written to storage blocks. In a preferred embodiment a collection of disk drives are formatted with 520 bytes of data per sector. For each 4,096-byte file block, a corresponding 64-byte block-appended checksum is appended to the file block with the first 7 sectors including most of the file block data while the 8th sector includes the remaining file block data and the 64-byte block-appended checksum.

公开(公告)号：EP1311949A2

公开(公告)日：2003-05-21

申请号：EP01965976.2

申请日：2001-08-17

Applicant: Network Appliance, Inc.

Inventor： LEWIS, Blake ,  EDWARDS, John, K. ,  VISWANATHAN, Srinivasan

IPC: G06F11/14

CPC classification number: G06F11/14 ,  G06F11/1435 ,  G06F2201/84 ,  Y10S707/99931 ,  Y10S707/99956

Abstract: The invention provides an improved method and apparatus for creating a snapshot of a file system. In a first aspect of the invention, a 'copy-on-write' mechanism is used. An effective snapshot mechanism must be efficient both in its use of storage space and in the time needed to create it because file systems are often large. The snapshot uses the same blocks as the active file system until the active file system is modified. Whenever a modification occurs, the modified data is copied to a new block and the old data is saved (henceforth called 'copy-on-write'. In this way, the snapshot only uses space where it differs from the active file system, and the amount of work required to create the snapshot is small. In a second aspect of the invention, a record of which blocks are being used by the snapshot is included in the snapshot itself, allowing effectively instantaneous snapshot creation and deletion.

公开(公告)号：EP1311949B1

公开(公告)日：2011-03-30

申请号：EP01965976.2

申请日：2001-08-17

Applicant: Network Appliance, Inc.

Inventor： LEWIS, Blake ,  EDWARDS, John, K. ,  VISWANATHAN, Srinivasan

IPC: G06F11/14

CPC classification number: G06F11/14 ,  G06F11/1435 ,  G06F2201/84 ,  Y10S707/99931 ,  Y10S707/99956

Abstract: The invention provides an improved method and apparatus for creating a snapshot of a file system. In a first aspect of the invention, a 'copy-on-write' mechanism is used. An effective snapshot mechanism must be efficient both in its use of storage space and in the time needed to create it because file systems are often large. The snapshot uses the same blocks as the active file system until the active file system is modified. Whenever a modification occurs, the modified data is copied to a new block and the old data is saved (henceforth called 'copy-on-write'. In this way, the snapshot only uses space where it differs from the active file system, and the amount of work required to create the snapshot is small. In a second aspect of the invention, a record of which blocks are being used by the snapshot is included in the snapshot itself, allowing effectively instantaneous snapshot creation and deletion.

公开(公告)号：EP1325415B1

公开(公告)日：2005-08-03

申请号：EP01979574.9

申请日：2001-10-04

Applicant: NETWORK APPLIANCE, INC.

Inventor： VISWANATHAN, Srinivasan ,  KLEIMAN, Steven, R.

IPC: G06F11/20

CPC classification number: G06F11/2082 ,  G06F11/1471 ,  G06F11/2064 ,  Y10S707/99953 ,  Y10S707/99955

Abstract: The invention provides a method and system for recovery of file system data in file servers having mirrored file system volumes. The invention makes use of a 'snapshot' feature of a robust file system (the 'WAFL File System) to rapidly determine which of two or more mirrored volumes is most up-to-date, and which file blocks of the most recent mirrored volume have been changed from each one of the mirrored file systems. In a preferred embodiment, among a plurality of mirrored volumes, the invention rapidly determines which is the most up-to-date by examining a consistency point number maintained by the WAFL File System at each mirrored volume. The invention rapidly pairwise determines what blocks are shared between that most up-to-date mirrored volume and each other mirrored volume, in response to a snapshot of the file system maintained at each mirrored volume and are stored in common pairwise between each mirrored volume and the most up-to-date mirrored volume. The invention re synchronizes only those blocks that have been changed between the common snapshot and the most up-to-date snapshot.