The purpose is to recover the largest amount of data as quickly as possible, and to establish exactly which sectors are the problematic ones. To put it simply, ddrescue starts at the end of each skipped section, and works backwards till it hits a bad sector. If a sector can’t be copied, or is even particularly slow in responding, ddrescue jumps ahead, hopefully beyond the problem. For a drive that’s working perfectly, this operation completes without issue and the whole drive is copied. First, it copies a sector at a time until it hits an error. To get ddrescue running, we give it an input, an output, and a mapfile.ĭdrescue /dev/sda diskimage.img mapfile.logīy default, ddrescue goes through three phases of rescue. Because there is record of the missing chunks, we can keep trying to read the missing parts, and maybe recover more data. ddrescue makes a note of the error, leaves a blank spot in the output file, and continues transferring what data it can. When dd encounters a read error, it stops the transfer and displays the error. It’s a descendant of sorts of the venerable dd disk copy tool, but with an important difference. The amateur sysadmin has a potent tool in his toolkit: ddrescue. If only there was a way to manage those unreadable sectors. The ironic part is that it’s usually only a tiny percentage of the disk that’s unreadable. An unreadable sector in the middle of a file will kill a file transfer, or maybe even make the device unmountable. When the spare sectors are gone, the disk begins accumulating unreadable sectors. As sectors begin to become unreliable, they are retired, and spare sectors are used instead. This is an expected process, and modern drives are built with spare sectors to fend off the inevitable.
#Spinrite 6 stuck full
If the file transfer fails because of the dying drive, or you need a full disk image, it’s time to pull out some tools and get to work.Īs a hard drive degrades, individual sectors can become unreadable. If you’re lucky, you can just copy your files and call it a day.
Another option is booting off a Linux DVD or flash drive, and accessing the drive in place. One of the USB to SATA cables available on your favorite online store is a great way to recover data. A truly dead drive is a topic for another time, but if the drive is alive enough to show up as a block device when plugged in, then there’s hope for recovering the data. Don’t turn to one of these questionable fixes unless you’ve exhausted the safer options.įor the purpose of this article, we’ll assume the problem is the hard drive, and not another component like a power supply or SATA cable causing problems. The downside is the potential for condensation inside the drive. The temperature change can help with stiction, and freezing the drive could potentially help an overheating drive last a bit longer. This could actually be useful in a couple instances. Another trick I’ve heard repeatedly is to freeze a hard drive before trying to read data off of it. One of my favorites is the official solution to stiction for old drives: Smack it with a mallet. There are some legends and old stories about hard drive repair. Those backups are up to date, right? Right? The clicking sound coming from the tower probably isn’t a good sign either. Few things bring a creeping feeling of doom like a computer that hardlocks and then refuses to boot. It should have been another fine day, but not all was well in paradise.