dd is a traditional utility for binary data copies

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5
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2answers
207 views

dd writes to CF with delay

I have an old 64MB CF card which I use in my laptop(kernel 2.6.38) with CardBus adapter. If I write a 64MB image to this CF card, then the write speed is more than 200MB/s: T42 ~ # fdisk -lu Disk ...
2
votes
2answers
82 views

Multiple passes of wiping disk with `dd`

I want to use dd to overwrite a disk multiple times to destroy data beyond recovery. I know I could use dd if=/dev/zero/ of=/dev/sdx/ to do a pass with zeros, or dd if=/dev/null/ of=/dev/sdx/ to ...
1
vote
1answer
2k views

Copy MBR and boot partition to a smaller disk

I'm using a 32GB SD card for my raspberry pi. I have successfully transferred the operating system (Archlinux ARM) to a usb harddrive. Which means that I only need the boot partition on the SD card. ...
1
vote
1answer
23 views

Can the BS option cause data inconsistency with dd?

I have a laptop partition (truecrypt) backed up with dd since it's impossible to back it up with anything else but do a raw bit by bit copy like: dd if=/dev/sda of=imagefile.img I can of course ...
3
votes
3answers
49 views

Resuming a DD of an entire disk

I'm overwriting my hard drive with random data using the good old dd: dd if=/dev/urandom of=/dev/disk/by-uuid/etc bs=512 It's a 2TB array and my MacBook (running Linux, ok?) can only write data at ...
2
votes
4answers
1k views

Why is writing SLOW on raw device, and FAST on filesystem (USB key)?

I have a USB key (PQI U822V-Speedy 32G) that I am trying to benchmark quick'n'dirty on Linux. I'm testing write bandwith. dd on raw partition I created a partition starting at sector 2048, then did ...
11
votes
2answers
400 views

Why does dd from /dev/urandom stops early? [duplicate]

On my current linux system (debian jessie amd64), I am getting different behavior for dd using /dev/urandom (/dev/random behavior is properly documented). If I naively want 1G of random data: $ dd ...
4
votes
2answers
5k views

How to use SSH to make a dd copy of disk A from host B and save on disk B?

I want to make remote backups from disk A at will using SSH from computer B. I want to save the backups to disk B. How can I do this? I've tried using $ ssh hostname@my.ip.add.ress "sudo dd ...
3
votes
3answers
100 views

How to inspect the contents of /dev/sdt?

I have what I hope is not a huge problem, but could end up being a very large problem. For some context, I mistakenly ran this command on my 27'' iMac: sudo dd if=ubuntu-rescue.img of=/dev/sdt ...
23
votes
5answers
19k views

Is it possible to mount a gzip compressed dd image on the fly?

I like create an image backup for the first time I'm backing up a system. After this first time I use rsync to do incremental backups. My usual image backup is as follows: Mount and zero out the ...
7
votes
2answers
5k views

Create file image container

I would like to create a 100GB file to use as a file-system. The file will be stored on an encrypted volume, so the file/file-system itself does not need to be (further) encrypted. Searching has ...
3
votes
4answers
2k views

Fast Way to Randomize HD?

I've read about how to make hard drives secure for encryption, and one of the steps is to write random bits to the drive, in order to make the encrypted data indistinguishable from the rest of the ...
0
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0answers
33 views

Why dd reads from output device?

While dding a CentOS 7 x86_64 DVD image to a USB drive (sdb), I monitored the progress with iostat. It kept alternating between mostly writing to the USB drive: Device: tps kB_read/s ...
0
votes
1answer
47 views

What does “dd” stand for? [duplicate]

What does dd stand for? I've always referred to it colloquially as "Disk Destroyer", but what are the "official" words that make up the acronym/command? According to this link and this link it could ...
0
votes
1answer
67 views

Delete labelled partition non interactively with one command

I know about fdisk and parted, but I was not able to figure out an non interactive way to delete a labelled partition. I imagine something like <command> <action> /dev/disk/by-label/LABEL ...
1
vote
0answers
22 views

From a sparse file to a block device

I have a system image sparse file which actual size is only a few MBs but the "apparent size" is about 1GB. I'm trying to write it to a block device efficiently (without the holes). Here are some ...
3
votes
1answer
103 views

losetup /dev/loop0 disappears after some time

at the moment I do some tests with loop devices on Linux/Ubuntu. In a small test script I have the following commands: #!/bin/sh rm testfile.x dd if=/dev/zero of=testfile.x bs=1M count=1200 losetup ...
58
votes
10answers
32k views

How do I know if dd is still working?

I've not used dd all that much, but so far it's not failed me yet. Right now, I've had a dd going for over 12 hours - I'm writing an image back to the disk it came from - and I'm getting a little ...
8
votes
3answers
124 views

How can `dd` be used to right-shift data blocks?

Consider a 100MB raw block device as a simple example. That is 204800 blocks of 512 bytes each for a total of 102760448 bytes. The challenge is to shift the first 98MB (200704 blocks) so there is a ...
1
vote
1answer
56 views

Can I use dd to quickly resilver a ZFS mirror disk?

My ZFS pool consists of two mirrored disks. I have two more disks which I plan to use for rotating offsite backups. The first backup disk was added to the zpool and has nearly completed resilvering. ...
0
votes
0answers
53 views

how to write dd command to replace backup image of root partition?

I have installed rhel6.5 in my pc. After that I have changed some configurations in file system. now I have taken backup image of /dev/sda1 which is a root partition of 15gb in size using the command ...
3
votes
0answers
41 views

Hard Drive reporting all 1's after parted

So I have a 3TB hard drive /dev/sdc that I am trying to create a partition on. Before this point, I had the issues described below, I transfered the drive to a Windows 7 computer and created a GPT on ...
1
vote
3answers
39 views

Software RAID10 setup writes small files extremely slowly, is this normal?

I have a software RAID-10 setup on Linux 3.16.6-203.fc20.x86_64, with 1.2 metadata and the default chunk size (512K): $ cat /proc/mdstat md0 : active raid10 sdc1[4] sdb1[0] sdd1[2] sde1[3] ...
1
vote
1answer
61 views

mounting partition images made with dd

is there a way to mount and access a single partition on any mountpoint in my filesystem or must I use disk images and mount with offset? I made a partiton image with dd bs=4M if=/dev/sdb1 ...
1
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0answers
38 views

dd over smb to reformat ntfs as ext3

I've been told it's possible to use dd to reformat a portion of a Windows share drive from NTFS to ext3. I'd like to do this to be able to preserve permissions when using rsync for backups, but I ...
1
vote
3answers
58 views

Can I backup a 1TB drive onto a 750GB drive?

I want to backup a larger harddrive (1000GB), but sadly, I only have a smaller harddrive (750GB) available. In this particular case, I do not want to copy over the files, I want to backup the ...
2
votes
0answers
103 views

Write the same file multiple times to one file using dd

I am trying to create large dummy files on a drive using dd. I am currently doing this: #!/bin/bash writeFile(){ #$1 - destination directory/filename, $2 - source filepath $3 - blocksize, $4 - ...
1
vote
2answers
34 views

How can I see processes being run by another instance of root on my Beaglebone

I am installing a Raspbian Linux image onto an sd card inserted into my BeagleBone Black. I will use this later in my Raspberry Pi. To do this, I am using the dd command from my MacBook Pro (via ...
1
vote
1answer
47 views

hexedit: change number of columns (bytes per line)

I am using hexedit to show/edit disk MBR (512 Bytes, copied with dd). When I open the file, hexedit displays the file as 9 columns, 4 bytes per column (36 bytes per line). That is very unfortunate. I ...
1
vote
1answer
294 views

What does the command pkill -USR1 -n -x dd mean exactly?

I am using dd to do a network transfer of a disk image to an sd card on my BeagleBone. Using pkill -USR1 -n -x dd in an ssh connection to this BeagleBone gives me a status update of the transfer ...
3
votes
1answer
40 views

How to make dd fail if it invalid skip value is specified?

When I invoke dd with an invalid value for skip it prints an error message and does nothing, but doesn't return with a value different from 0, e.g. $ cd /tmp $ mkdir xy $ cd xy $ truncate -s 2M ...
5
votes
3answers
405 views

Why is dd not protected against writing on the active disk ?

I use dd a lot. I live in a contant fear of making a mistake one day, for example writing on sda (computer disk) instead of sdb (USB disk) and then erasing everything I have on my computer. I know dd ...
1
vote
3answers
1k views

How to convert dd disk image to Clonezilla?

I have disk image from VirtualBox, it is a raw image, just like dd makes it, now I would like to restore the system to real machine using Clonezilla. However Clonezilla does not recognize the image ...
2
votes
3answers
195 views

can 'dd' be used to clone to a smaller HDD, knowing that partitions will need editing?

I've used dd to clone disks like this: dd if=/dev/sdb of=/dev/sda bs=4096 conv=notrunc,noerror,sync And it's always worked fine. Any and all docs on 'dd' take pains to remind you that the target ...
3
votes
2answers
144 views

How to parallelize dd?

I'm currently having trouble with dd invoked with a sparse file as input (if) and a file as output (of) with conv=sparse. dd seems to be using one core of the CPU (Intel(R) Core(TM) i7-3632QM CPU @ ...
4
votes
2answers
79 views

why do people use “notrunc” when making an ISO from a DVD?

There are many articles on the web that describe a command-line to make an ISO image from a DVD-Video disc like this: dd if=/dev/sr0 of=mydvd.iso conv=noerror,sync,notrunc I'd like to uderstand why ...
3
votes
1answer
130 views

Differences between dd in Mac OS X and Linux

When using Linux (Debian), I often use dd to copy a disk image to an SD card. I have written a script that throws an error if the device file specified in the "of" option is too large. This keeps me ...
2
votes
2answers
112 views

dd taking weeks

A few days ago, I got the message "Windows detected a hard disk problem". I got a new hard drive, and booted into Ubuntu using a live USB. I started cloning the failing disk using sudo dd ...
7
votes
5answers
5k views

How do I suppress dd output?

I have a bash script that creates some file using dd. The problem is dd throws a great amount of output that is going to mess with the output of my script. Searching around I've found a solution: dd ...
4
votes
1answer
51 views

dd, seek with one block size, write with another block size

Background Info: Copying some .bin files to an SD card (to be read by an embedded device, no filesystem) Commissioning the card requires some segments to be wiped (i.e. zero'd), and others to have ...
0
votes
1answer
140 views

Is it possible to use dd to clone only the part of the hard drive which is used?

if only 1/3 of a 300GB hard disk is used. Is it possible to use dd to clone the drive (but only the 100GB that is used)? dd if=/dev/sda of=clone.img
2
votes
1answer
122 views

Equivalent of memmove on files: copy a range of bytes to an earlier position

What is an equivalent of memmove on files with the same input and output file, which works with large files? dd works when I move the file contents towards the right, but not if I move the contents ...
0
votes
0answers
88 views

GNU Guix usb-install freezes at GRUB after boot

I wanted to try out the GNU usb install that was released with Guix 0.7. The problem is that when I try to boot from the USB, it freezes, with the word GRUB and a flashing type line. I followed the ...
1
vote
2answers
245 views

how to use dd to fill drive with 1's

Filling a drive with /dev/urandom seems to be very slow, so I created a file filled with FF: dd if=/dev/zero ibs=1k count=1000 | tr "\000" "\377" >ff.bin I'd like to fill the drive with copies ...
0
votes
3answers
956 views

dd write vs read performance

I have recently done some performance tests on a new server (using dd) and wonder why read performance is so much worse than write performance? Shouldn't it be another way around? file size was in ...
3
votes
0answers
40 views

Is this a correct way to back up one big drive to two smaller ones?

I have a pre-fail drive, and while I'm waiting for replacement I am trying to do full back up to two smaller drives. Given that drive is 3TG and ones I have are 1.5 and 2TB, is this a correct way to ...
4
votes
1answer
308 views

Partially overwrote /dev/sda, can I recover anything?

I was messing around with my new hard drive, which only contains some personal files, and to check its write speed, I typed: sudo dd if=/dev/zero of=/dev/sda, /dev/sda/ being the new 2 TB connected to ...
11
votes
2answers
964 views

Is dd able to overwrite parts of a file?

I have a 1TB big file (disk-image from a damaged drive) and a 1.3MB small file (beginning of a disk-file). Using the contents of the small file, I want to overwrite portions of the big file. That is, ...
1
vote
1answer
108 views

How to use pv with dd?

I'm trying to use dd with pv to write an iso to a usb drive. I did: iso="myiso.iso"; dd if="$iso" bs=1M | pv --eta --size $(ls -l "$iso" | awk '{print $5}') --progress --bytes --rate --wait > ...
2
votes
2answers
464 views

dd to clone to smaller sdcard

One of my Raspberry Pi's is using a 4GB SDcard for the root/boot filesystem. As seen when mounted on another system: Disk /dev/sdc: 3904 MB, 3904897024 bytes 121 heads, 62 sectors/track, 1016 ...