Shulou(Shulou.com)06/03 Report--

Brief description of the failure:

The device that requires data recovery is an NetApp storage, which consists of 24 disks. Because the administrator deleted the folder for a long time, it took several months to delete it.

Recoverability judgment:

Due to the nature of the file system in NetApp, WAFL is a "Write Anywhere File Layout", that is, "write to the file layout anywhere", so it is unlikely to overwrite the previous data and can be used for tentative data recovery.

Data recovery steps:

1. Analyze the data structure of NetApp. Because different WAFL file system versions are different and vary greatly, it is necessary to judge according to the structure of nodes, such as data block node pointer, or 8 bytes or 12 bytes. After manual analysis, it is concluded that the version in this case is WAFL7.3.4, and the block pointer is 8 bytes.

2, after observation, the file system uses a blocksize of 8 sectors, in which the first four sectors are data blocks and the latter sector is the block mark. In some versions, the contents of the last sector are compressed to the end of the last sector of the data sector, in order to save disk capacity.

Block check sector

3, it is important to analyze the directory structure, which stores the meta-information of folders, files, and the file system itself. This structure stores the node of the file, which is unique, the node of the parent folder, and is consistent with the information in the data node.

Catalogue

4. After analyzing these important structures, we will scan all the node information and directory information we need and store them in the database.

5, according to the needs of users, look up the needed files or folders in the database, establish the directory tree we need, understand the algorithm, write the corresponding program according to the requirements, and provide the root directory. The follow-up basically depends on the program to run out.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.