The data recovery tool for system administrators

Test Programs

Because of its numerous testing and monitoring programs, Linux makes it possible for the user to track down hardware problems. As a result, SystemRescueCD has a practical mix of tools with graphical interface and others that run on a terminal.

You will find a hardware lister, which graphically displays the hardware components of the target system in the submenu System . In the same place, you will also find the Htop tool, which displays resource consumption for each currently executing process. This can be especially useful when you need to determine exact revision numbers for particular hardware components used in the computer, for example, to do a firmware update.

The graphical interface uses information from the lshw command, which frequently reveals even more detailed information. Iotop is an additional tool that is likewise already preinstalled in SystemRescueCD.

This tool alerts the user to occasional spikes in the system load and also high latency times due to issues associated with individual hardware components. Because these issues might cause system-wide impairment due to a flood of IRQ requests, this program is a favorite among server administrators.

Data Recovery and Security

One special focus of SystemRecsueCD is data recovery. Many tools have been integrated into this Gentoo derivative for the care and maintenance of mass storage. Of particular note are entries for Show Filesystems , GParted , Partimage , and Testdisk , which are found in the System submenu.

The Show Filesystems application opens a terminal and invokes the command line program fsarchiver. Behind the Partimage entry, you will find the current 0.6.9 version of the Ncurses program partition image, which you can use to set up an image of hard drive partitions in just a few steps.

You are not restricted to data partitions, because you can also create complete system partitions. The latter make a snap shot available in case a mass storage device fails. Installing and configuring operating systems and application programs can be time-consuming. If you have a snapshot of the operating system, these tasks fall away (Figure 5).

Figure 5: Old-fashioned but still useful: a partition image.

The graphical program GParted lets you edit partition tables for mass storage devices. This program understands a multitude of different filesystems and is therefore useful in heterogenous environments.

TestDisk is a terminal program that is a high-performance tool for reconstructing mass storage partitions when these have become unreadable. The software can also reinstate the boot capability for mass storage if the boot sector has been destroyed by malware or by accidental error.

Grsync, a graphical program, is listed in the same submenu. It is helpful for synchronizing directories and files. To perform its tasks, Grsync relies on the command-line tool rsync and uses the most important of its parameters to secure data stores. This software can handle both locally stored data and data stored online (Figure 6).

Figure 6: Grsync can synchronize your data with just a few mouse clicks.

Rsnapshot is a similar program. Based on Rsync and accessible via the terminal, it can prepare image snapshots of entire partitions in much the same way that Partition Image can. Rsnapshot is also suitable for use with external USB hard drives when they serve as the backup medium.

A special feature of this software is that it only saves unmodified data once to a single target medium when several snapshots of the data are taken. This saves storage by means of the hardlinks that are set for data that has already been saved when more recent snapshots are made.

The disadvantage to this method is that more recent snapshots are no longer readable if only a small amount of data has been modified or if the original snapshot has been damaged and can no longer be reconstructed. This can be a special problem when only a few of the original files have been modified.

Tob – which stands for tape-oriented backup – functions purely as a backup program. It can deposit backups on tapes and traditional filesystems. This terminal program offers numerous options, which can be displayed via tob --help .

PhotoRec works together with TestDisk on data reconstruction. It is not found on the desktop menu but is invoked from the terminal. PhotoRec comes into play when the user is dealing with data that becomes inaccessible due to error or hardware defect. In spite of what its name might suggest, PhotoRec is definitely not limited in its application to digital image files. This application can also reconstruct numerous other file formats.