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- updating email addresses (bottom of page and "Contact me" in index.html
- updating site
  Please do not commit anything in trunk/www
  This folder is updated by script 2site and any manual changes are
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86 WARNING<br>
87 This is the UNSTABLE version of Clonezilla-SysRescCD<br>
88 To access our current stable version, please click <a href="../index.html">here</a>
89 </div>
90 <div id="header">
91 <H2>Clonezilla-SysRescCD</H2>
92 <H3>Offline Documentation: Data Recovery</H3>
93 <div style="margin:0; padding: 3px; width: 980; position relative;">
94 <div style="position: absolute; left: 0px;"><H4>30/06/2011 - v 3.2.0</H4></div>
95 <div style="position: absolute; right: 0px;"><H4>Last update: 06/06/2011</H4></div>
96 </div>
97 </div>
98 <div id="linkline">
99
100
101 <!-- <a href="features.html">Features</a>-->
102 <a class="here" href="../README.html">Offline Documentation</a>
103
104
105
106
107
108 <!-- docline-top-->
109 <div id="docline-top"> <a href="partitions.html">&lt; PREV</a> <a href="../README.html">UP</a> <a href="own-scripts.html">NEXT &gt;</a> </div>
110 </div>
111 <div id="contarea">
112 <div id="content">
113 <a name="recover-top"></a>
114
115 <!-- On the CD -->
116
117 <H2 style="margin-top: 0;"><a name="recover-intro"></a>Intro <span class="hideprint">[<a href="#help-top" title="go to top of the page">^</a>]</span></H2>
118
119 <p>Deleted or "lost" files can be recovered from failed or formatted drives and partitions, cdroms and memory cards using the software available in <b>SystemRescueCD</b>.
120
121 Unless you can rule out hardware failure, you must not write to the failed device. The following software will passively try to recover your data from failed or failing hardware. If your data is not replaceable, do not attempt to write to the failed device if the following applications do not work but seek professional advice instead.<br>
122 <br>
123 If your device is damaged, it is advisable to image the device and work on the image file for data recovery. If hardware failure is not the problem, you can recover data directly from the device.<br>
124 <br>
125 To recover data from a failed device, you will need another device of equal or greater storage capacity onto which to save your data. If you need to make an image of the failed device, you will need yet another quantity of space.<br>
126 <br>
127 I should state here, that I haven't used any of these tools recently (other than plain and simple <b>dd</b>, a long time ago, which I found to be very slow), so I couldn't recommend any of them. Any comments on a tool's usability found in this page, is just what I found on the Net.</p>
128
129
130 <!-- Partition recovery -->
131 <H2><a name="recover-dr"></a>Partition recovery <span class="hideprint">[<a href="#help-top" title="go to top of the page">^</a>]</span></H2>
132
133 <p>If you made a mistake while partitioning and the partition no longer appears in the partition table, so long as you have not written data in that space, all your data is still there and can be restored.</p>
134
135 <p>When changing the partition table on your hard drive, you must ensure that no partition on the disk is mounted. This includes swap space. In order to restore your partition, execute:</p>
136
137 <p class="newcode">swapoff -a<br>
138 parted /dev/old_disk</p>
139
140 <p>Then, use the rescue option:</p>
141
142 <p class="newcode">rescue START END</p>
143
144 <p>where <b>START</b> is the area of the disk where you believe the partition began and <b>END</b> is it's end. If parted finds a potential partition, it will ask you if you want to add it to the partition table.</p>
145
146 <p><b>Note:</b> <a href="#recover-testdisk">TestDisk</a> can also be used to recover a "lost" partition.</p>
147
148 <!-- Disk recovery -->
149 <H2><a name="recover-dr"></a>Disk / files recovery <span class="hideprint">[<a href="#help-top" title="go to top of the page">^</a>]</span></H2>
150
151 <!-- dd -->
152 <H3><a name="recover-dd"></a>Using dd <span class="hideprint">[<a href="#help-top" title="go to top of the page">^</a>]</span></H3>
153
154 <p>In order to duplicate a disk to another disk, execute</p>
155
156 <p class="newcode">dd if=/dev/old_disk of=/dev/new_disk conv=noerror,sync</p>
157
158 <p>or to create an image file</p>
159
160 <p class="newcode">dd if=/dev/old_disk of=image_file conv=noerror</p>
161
162 <p>Be careful, if you are copying a disk, the destination must also be a disk, not a partition. If you are copying a partition, the destination partition must be large enough. Copying the whole disk is recommended.<br>
163 <br>
164 To speed up the copy process, you can append <b>bs=8k</b>, it will read/write the disk by 16 sectors at a time.</p>
165
166
167 <!-- dd_rescue -->
168 <H3><a name="recover-dd-rescue"></a>Using dd_rescue <span class="hideprint">[<a href="#help-top" title="go to top of the page">^</a>]</span></H3>
169
170 <p>Like dd, <a href="http://www.garloff.de/kurt/linux/ddrescue/" target="_blank">dd_rescue</a> does copy data from one file or block device to another. You can specify file positions (called seek and skip in dd). There are several differences:</p>
171
172 <ul>
173 <li>dd_rescue does not provide character conversions.</li>
174 <li>The command syntax is different. Call <b>dd_rescue -h</b>.</li>
175 <li>dd_rescue does not abort on errors on the input file, unless you specify a maximum error number. Then dd_rescue will abort when this number is reached.</li>
176 <li>dd_rescue does not truncate the output file, unless asked to.</li>
177 <li>You can tell dd_rescue to start from the end of a file and move backwards.</li>
178 <li>It uses two block sizes, a large (soft) block size and a small (hard) block size. In case of errors, the size falls back to the small one and is promoted again after a while without errors.</li>
179 <li>It does not (yet) support non-seekable in- or output.</li>
180 </ul>
181
182 <p>In order to duplicate a disk to another disk, execute</p>
183
184 <p class="newcode">dd_rescue -A -v /dev/old_disk /dev/new_disk</b></p>
185
186 <p>or to create an image file</p>
187
188 <p class="newcode">dd_rescue -A -v /dev/old_disk image_file</b></p>
189
190 <p>The copying should go very quickly until it hits a bad sector and then it will slow down to take smaller chunks of data. People have reported very good results with this technique.</p>
191
192
193 <!-- GNU ddrescue -->
194 <H3><a name="recover-gnu-ddrescue"></a>Using GNU ddrescue <span class="hideprint">[<a href="#help-top" title="go to top of the page">^</a>]</span></H3>
195
196 <p>The GNU site describes GNU ddrescue as a data recovery tool, and lists these features:</p>
197
198 <ul>
199 <li>It copies data from one file or block device (hard disc, CD-ROM, etc) to another, trying hard to rescue data in case of read errors.</li>
200 <li>It does not truncate the output file if not asked to, so every time you run it on the same output file, it tries to fill in the gaps.</li>
201 <li>It is designed to be fully automatic.</li>
202 <li>If you use the log file feature of GNU ddrescue, the data is rescued very efficiently (only the needed blocks are read). Also you can interrupt the rescue at any time and resume it later at the same point.</li>
203 <li>The log file is periodically saved to disc. So in case of a crash you can resume the rescue with little recopying.</li>
204 <li>If you have two or more damaged copies of a file, CD-ROM, etc, and run GNU ddrescue on all of them, one at a time, with the same output file, you will probably obtain a complete and error-free file. The probability of having damaged areas at the same places on different input files is very low. Using the log file, only the needed blocks are read from the second and successive copies.</li>
205 <li>The same log file can be used for multiple commands that copy different areas of the file, and for multiple recovery attempts over different subsets.</li>
206 </ul>
207
208 <p>The algorithm of GNU ddrescue is as follows:</p>
209
210 <ol>
211 <li>Optionally read a log file describing the status of a multi-part or previously interrupted rescue.</li>
212 <li>Read the non-damaged parts of the input file, skipping the damaged areas, until the requested size is reached, or until interrupted by the user.</li>
213 <li>Try to read the damaged areas, splitting them into smaller pieces and reading the non-damaged pieces, until the hardware block size is reached, or until interrupted by the user.</li>
214 <li>Try to read the damaged hardware blocks until the specified number of retries is reached, or until interrupted by the user.</li>
215 <li>Optionally write a log file for later use.</li>
216 </ol>
217
218 <p><b>Note:</b> GNU ddrescue is considered to be the best recovery tool available.</p>
219
220 <p>In order to duplicate a disk to another disk, execute</p>
221
222 <p class="newcode">ddrescue -vr3 /dev/old_disk /dev/new_disk logfile</b></p>
223
224 <p>or to create an image file</p>
225
226 <p class="newcode">ddrescue -vr3 /dev/old_disk image_file logfile</b></p>
227
228 <p>If the disk is failing fast and you want to get the most data out of it on the first try, you should probably use "<b>-n</b>" on the first run. This will avoid splitting error areas. Subsequent runs can use "<b>-r1</b>" or "<b>-r3</b>", without "<b>-n</b>", to retry those error areas.</p>
229
230 <p>To summarise, we execute:</p>
231
232 <p class="newcode">ddrescue -vn /dev/old_disk image_file logfile<br>
233 ddrescue -v -r3 -C /dev/old_disk image_file logfile</p>
234
235 <p><b>Note:</b> When working with CD-ROMs you should probably specific "<b>-b 2048</b>"</p>
236
237
238 <!-- Foremost -->
239 <H3><a name="recover-foremost"></a>Using Foremost <span class="hideprint">[<a href="#help-top" title="go to top of the page">^</a>]</span></H3>
240
241 <p><a href="http://foremost.sourceforge.net/" target="_blank">Foremost</a> is a console program to recover files based on their headers, footers, and internal data structures. This process is commonly referred to as data carving. Foremost can work on image files, such as those generated by dd, Safeback, Encase, etc, or directly on a drive. The headers and footers can be specified by a configuration file or you can use command line switches to specify built-in file types. These built-in types look at the data structures of a given file format allowing for a more reliable and faster recovery.</p>
242
243 <p>It can be run on an image file created with any of the above tools, to extract files:</p>
244
245 <p class="newcode">foremost -i image -o /recovery/foremost</p>
246
247 <p>Foremost can be instructed to recover only specific file types, using the <b>-t</b> command line parameter. In the following example Foremost will extract only jpg files:</p>
248
249 <p class="newcode">foremost -t jpg -i image -o /recovery/foremost</p>
250
251 <p>Available types are: jpg, gif, png, bmp, avi, exe (Windows binaries and DLLs), wav, riff, wmv (will extract wma also), mov, pdf, ole (will extract any file using the OLE file structure; this includes PowerPoint, Word, Excel, Access, and StarWriter), doc, zip (will extract .jar files and Open Office docs as well; this includes SXW, SXC, SXI, and SX? for undetermined OpenOffice files), rar, html and cpp.</p>
252
253 <!-- TestDisk -->
254 <H3><a name="recover-testdisk"></a>Using TestDisk <span class="hideprint">[<a href="#help-top" title="go to top of the page">^</a>]</span></H3>
255
256 <p><a href="http://www.cgsecurity.org/wiki/TestDisk" target="_blank">TestDisk</a> was primarily designed to help <b>recover "lost" partitions</b> and/or <b>make non-booting disks bootable again</b> <i>when</i> these symptoms are caused by <i>faulty software</i>, certain types of <i>viruses</i> or <i>human error</i> (such as <i>accidentally</i> deleting a Partition Table). Partition table recovery using TestDisk is really easy.<br>
257 <br>
258 TestDisk can</p>
259
260 <ul>
261 <li> Fix partition table, recover deleted partition</li>
262 <li> Recover FAT32 boot sector from its backup</li>
263 <li> Rebuild FAT12/FAT16/FAT32 boot sector</li>
264 <li> Fix FAT tables</li>
265 <li> Rebuild NTFS boot sector</li>
266 <li> Recover NTFS boot sector from its backup</li>
267 <li> Fix MFT using MFT mirror</li>
268 <li> Locate ext2/ext3 Backup SuperBlock</li>
269 </ul>
270
271 <p>Some great tutorials are available at TestDisk's site: "<a href="http://www.cgsecurity.org/wiki/TestDisk_Step_By_Step" target="_blank">TestDisk Step By Step</a>", "<a href="http://www.cgsecurity.org/wiki/Running_TestDisk" target="_blank">Running TestDisk</a>", "<a href="http://www.cgsecurity.org/wiki/Data_Recovery_Examples" target="_blank">Data Recovery Examples</a>" etc.
272 </p>
273
274 <!-- PhotoRec -->
275 <H3><a name="recover-photorec"></a>Using PhotoRec <span class="hideprint">[<a href="#help-top" title="go to top of the page">^</a>]</span></H3>
276
277 <p><a href="http://www.cgsecurity.org/wiki/PhotoRec" target ="_blank">PhotoRec</a> is file data recovery software designed to recover "lost" files including video, documents and archives from Hard Disks and CDRom and "lost" pictures (thus, its 'Photo Recovery' name) from digital camera memory. PhotoRec ignores the filesystem and goes after the underlying data, so it will still work even if your media's filesystem has been severely damaged or re-formatted.<br>
278 <br>
279 For more safety, PhotoRec uses read-only access to handle the drive or memory support you are about to recover "lost" data from.<br>
280 <br>
281 <b>Important</b>: As soon as a pic or file is accidentally deleted, or you discover any missing, do NOT save any more pics or files to that memory device or hard disk drive; otherwise you may overwrite your "lost" data. This means that even using PhotoRec, you must not choose to write the recovered files to the same partition they were stored on.<br>
282 <br>
283 A great tutorial titled "<a href="http://www.cgsecurity.org/wiki/PhotoRec_Step_By_Step" target="_blank">PhotoRec Step By Step</a>" can be found at PhotoRec's site.</p>
284
285
286
287 <!-- Links -->
288 <H2><a name="recover-links"></a>Links &amp; resources <span class="hideprint">[<a href="#help-top" title="go to top of the page">^</a>]</span></H2>
289
290 <p>This page is a compilation of the following pages:</p>
291
292 <p>DataRecovery<br>
293 &nbsp;&nbsp;&nbsp;&nbsp;<a href="https://help.ubuntu.com/community/DataRecovery" target="_blank">https://help.ubuntu.com/community/DataRecovery</a></p>
294
295 <p>Hard Drive Recovery, Ubuntu-Style<br>
296 &nbsp;&nbsp;&nbsp;&nbsp;<a href="http://blogs.sun.com/superpat/tags/ddrescue" target="_blank">http://blogs.sun.com/superpat/tags/ddrescue</a></p>
297
298 <p>Recover Data and (deleted) Partition with Linux from Hard Drives, CD-ROMs or DVDs<br>
299 &nbsp;&nbsp;&nbsp;&nbsp;<a href="http://sysblogd.wordpress.com/2008/01/05/data-recovery-with-linux-from-hard-drives-cd-roms-or-dvds/" target="_blank">http://sysblogd.wordpress.com/2008/01/05/data-recovery-with-linux-from-hard-drives-cd-roms-or-dvds/</a></p>
300
301 <p>dd_rescue<br>
302 &nbsp;&nbsp;&nbsp;&nbsp;<a href="http://www.garloff.de/kurt/linux/ddrescue/" target="_blank">http://www.garloff.de/kurt/linux/ddrescue/</a></p>
303
304 <p>gddrescue: a tool for recovering data from damaged media<br>
305 &nbsp;&nbsp;&nbsp;&nbsp;<a href="http://debaday.debian.net/2007/12/12/gddrescue-a-tool-for-recovering-data-from-damaged-media/" target="_blank">http://debaday.debian.net/2007/12/12/gddrescue-a-tool-for-recovering-data-from-damaged-media/</a></p>
306
307 <p>Foremost<br>
308 &nbsp;&nbsp;&nbsp;&nbsp;<a href="http://foremost.sourceforge.net/" target="_blank">http://foremost.sourceforge.net/</a></p>
309
310 <p>TestDisk<br>
311 &nbsp;&nbsp;&nbsp;&nbsp;<a href="http://www.cgsecurity.org/wiki/TestDisk" target="_blank">http://www.cgsecurity.org/wiki/TestDisk</a></p>
312
313 <p>PhotoRec<br>
314 &nbsp;&nbsp;&nbsp;&nbsp;<a href="http://www.cgsecurity.org/wiki/PhotoRec" target="_blank">http://www.cgsecurity.org/wiki/PhotoRec</a></p>
315
316
317 </div>
318
319
320
321 <!--<a name="template-top"></a>-->
322
323 <div id="footer">
324 <div id="docline-bottom"> <a href="partitions.html">&lt; PREV</a> <a href="../README.html">UP</a> <a href="own-scripts.html">NEXT &gt;</a> </div>
325 <p>Copyright: &#169; <a href="mailto:&#115;&#110;&#103;&#064;&#104;&#101;&#108;&#108;&#117;&#103;&#046;&#103;&#114;?subject=About Clonezilla-SysRescCD v 3.2.0" title="About Clonezilla-SysRescCD">Spiros Georgaras</a>, 2007-2011 &amp; <a href="mailto:&#115;&#097;&#110;&#100;&#103;&#116;&#120;&#064;&#103;&#109;&#097;&#105;&#108;&#046;&#099;&#111;&#109;?subject=About Clonezilla-SysRescCD v 3.2.0 documentation" title="About Clonezilla-SysRescCD Documentation">Jyrki Vesterinen</a>, 2010-2011<br /><br/>
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