Linux high-end: ReiserFS file system data recovery software

ReiserFS file system is a very good file system, especially for large files or a large number of small files, its processing power is very amazing. As far as the ReiserFS file system data recovery case that Darth data recovery experts participated in, the mail archive storage system, insurance company file archive storage, industrial and commercial tax and other national agency documents archived, etc., almost all use the ReiserFS file system. Novell's SUSE Linux Enterprise operating system defaults to the ReiserFS file system. In addition, the ReiserFS file system is sought after by many Linux vendors. Although its security is worthy of recognition, but the world is unpredictable, not all things can be 100% perfect, the data under the ReiserFS file system, once the problem occurs, it is more troublesome. Therefore, ReiserFS file system data recovery technology has become the focus of attention.

Figure 1: Darth technology ReiserFS file system data recovery experts really

Darth technology in the ReiserFS file system data recovery technology research earlier, not only a lot of practical experience ReiserFS file system data recovery case, also released China's first ReiserFS file system data recovery software D-Recovery for ReiserFS, which is a professional data software supporting ReiserFS file system.

D-Recovery for ReiserFS ReiserFS Data Recovery Software Features:

1. It is a professional ReiserFS file system data recovery software independently developed by Darth Technology, which damages the ReiserFS file system. The problem of data loss, such as file deletion, partition table information corruption, and super block corruption, is extremely high. This software is widely used in many large enterprise data storage applications.

2, Darth Technology independent intellectual property;

3, running on the windows platform (XP/2000/2003/2008/WIN7);

4, support ReiserFS file System;

5, full Chinese interface, easy to operate;

6, the partition table according to the ReiserFS file system caused by partition deletion, virus damage, sudden power failure, abnormal shutdown, etc. Lost data recovery is good.

7, for the ReiserFS file system due to super block information destruction, the partition mount does not cause data loss, the software can fictitiously generate super block information or find the super block backup, successfully recover the lost data.

Figure II Darth ReiserFS file system data recovery software package appearance

8, ReiserFS file system directory for damage caused by data loss data recovery effect is good.

9, for the file deleted by mistake in the ReiserFS file system, you can recover the lost file information through the log scan, and then recover the lost file;

10, the data after the ReiserFS file system is formatted Lost data recovery is good.

Figure 3: Darth ReiserFS file system data recovery software interface is very friendly

professional reflect ReiserFS file system data recovery success stories:

Project Name: Linux The operating system platform Reiserfs file system accidentally deletes the mail archive

Fault Description: In Linux startup, the process defaults to periodically delete data, with a period of 31 days. On the 31st day, the system automatically retrieves the archive file created for more than 31 days and executes the rm delete command operation. After about 2 days, the total data capacity was about 36TB, and the new data was about 1TB in the past two days, and the average logical volume was written to 66 groups of servers.

On-site situation: All DL320s servers have been shut down and stopped. Before the official data recovery, we randomly select one of the servers for data recovery test operation. We can only perform data mirroring through the server's two USB interfaces. And must do read-only operations, can not do any editing operations. There is an office of about 25 square meters next to the machine room, which can accommodate about 10 engineers at the same time. If the data recovery machine is placed on top of each other, up to 66 PCservers can be operated at the same time. The power supply on site is stable and the equipment room environment is very good.

Data Recovery Test Process:

1. Plug the USB bootable CD from Dass into the USB port on the HP PorLiant DL320s server, set it as a USB boot machine in bios, and pass the USB system. Install the P400raid card driver to find the target logical volume;

2. Fully mirror all the sectors of the logical volume to the 2T USB mobile hard disk by the sector-level mirroring tool (this 2TB mobile) The hard disk is plugged into another USB interface), and the img file is generated for data analysis.

3. Remove the 2TB hard disk with the img file from the USB hard disk box and access the PC prepared in advance. Data analysis on the Server. Mainly look at the Reiserfs file system, super blocks, nodes and comprehensive analysis of deleted data.

4, call the Darth ReiserFS file system data recovery software, according to the analysis results of the third part to delete the data search work.

5, randomly sampled from the deleted data, and extracted into a normal zip archive for testing.

6, compare the extracted data sample with the delete file log (deleteBitfile.log), and carefully check the file name to view the detailed information of the deleted file.

Data Recovery Results: Data recovery was successful.

About the ReiserFS file system:

The ReiserFS naming is derived from the author's last name, Hans Reiser. This log file system develops later than ext2/3. The technology uses a B-tree-based file system, which is characterized by the ability to handle large files to many small files with high efficiency; in fact, ReiserFS is even more efficient when processing files smaller than 1k. It can be about 10 times faster than ext3!

ReiserFS was originally the default file system used by Novell's SuSE Linux Enterprise until October 12, 2006, when it announced that it would adopt ext3 as the default in future versions.

Online resizing (can only be larger, online, offline means mounted or unmounted), you can use disk management mechanism such as LVM to modify, or not. For this reason, Namsys has tools that provide resizing when offline (you can adjust the zoom space or reduce the space).

Sail Packing reduces the fragmentation of internal disk space. This feature has made considerable progress compared to other file systems. It is also worth mentioning that in ReiserFS4, this feature is more powerful, while retaining the strengths and not affecting performance.

Compared with ext2 and ext3 in Linux Kernel 2.4, ReiserFS is 10 to 15 times faster when dealing with small files below 4KB (tail packing enable). This is a significant functional improvement for network services such as web news services, HTTP caching, and email systems that need to process large numbers of small files.

The process of rebuilding the ReiserFS index tree has caused a lot of controversy: if the file system is badly destroyed, the internal index tree will be invalid, and then the operation of rebuilding the index tree is more likely to Make this ruin situation worse, like pointing the index to unpredictable content. However, this operation is not part of normal operation, nor is it a normal file system check. Before this operation is run, there should be a clear prompt, which may occur after confirmation by the administrator.

However, to avoid misdirected file system processing, we do not recommend storing an image file of ReiserFS v3 in its original unencrypted or compressed form on a ReiserFS v3 partition. Formatting an existing ReiserFS v3 partition may also leave data plaguing the rebuild operation and reproduce the files on the old system. This vulnerability gives malicious users a chance to troubleshoot the rebuild process. After the metadata is checked by the file system, it will maintain the old state, and then destroying this place will make the contents of the file combined with the metadata of the file system in an unpredictable way. However, this issue has been resolved in ReiserFS 4.