Questions tagged [dd]

A common Unix program whose primary purpose is the low-level copying and conversion of raw data.

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Unexpected latency reading from /dev/zero

I am currently investigating IO issues in some hosts and encountered a completely unexpected behavior for me: reading 1M from /dev/zero takes over 100ms While testing the drives I used the following ...
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Cloned Disk with dd in Linux Live Image

I used dd to clone with an Ubuntu Live Image from a smaller SSD to a bigger one. During the cloning process Ubuntu freezed. I waited some time and did a hard shutdown. After rebooting it seems the ...
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How come I can't write to the last byte of the the last block?

I was doing some tests by writing random patterns of data at a block size of 512 bytes (the size of blocks on my drive) and dd fails at the last block saying that the device ran out of space. I was ...
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After cloning, the system Windows 8.1 shows the size of the smaller disk

I have ask a related question elsewhere. I have cloned 4TB HDD onto 8.TB but the system (Win 8.1) shows the size of the lower of the 2 disks, i.e. the size of the source while cloning. How do I assign ...
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Bad Superblock when mounting LVM SSD

I made a complete copy of my Fedora boot ssd using dd however the new drive does not boot correctly and is not mountable when connected via usb enclosure on a different machine. I get a bad superblock ...
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how to dd /dev/sdX to /dev/mmcblkX?

I made a Debian 10 system image in virtual machine and written it to external HDD. I wanted to copy the system to a laptop's disk, but it has SSD disk that shows up as /dev/mmcblk. My system has 3 ...
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Cloning my linux drive to another one with DD tool

I was using windows for quite a while and made my switch to linux mint. I did not know if the linux is really better, so i installed it onto secondary drive. Now i do not use anything else than linux, ...
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Hard drive stops working during ddrescue and is making odd sounds

We have an older HDD (WD Black 500 GB) that was still in use for the data it had but then at some point, Windows wouldn't boot with the drive installed. I checked with a Linux installation and the ...
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How can I recreate an installer iso from a usb (Mac/Windows) using dd?

I have read many "how do I write an iso to USB" questions. I am looking for a way to reverse the process. My question is about taking a USB stick containing a Windows installer or Mac ...
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Getting blocks of zeros after flashing SD card with dd

I've got a problem with writing an SD card with an image. What I want to do is to create an image of an SD card from files present on my hard drive. My plan is to: Create a loop device and connect it ...
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Migrate Operating System to a new Disk with dd or other linux tools

I have 1 TB HDD, and a new 250 GB SSD. The HDD has these partitions: 499 MB (EFI) 256 GB (Boot, Page File) - Only 120 GB of this partition is used. the rest is free. 499 MB (Recovery Partition) 736 ...
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How to checksum a SquashFS filesystem on partitionless HDD

# lsblk -f /dev/sda NAME FSTYPE FSVER LABEL UUID FSAVAIL FSUSE% MOUNTPOINT sda squashfs 4.0 # mount -v /dev/sda /mnt mount: /dev/sda mounted on /mnt. $ df -B1 Filesystem 1B-blocks Used ...
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Luks header overwritten with dd

I've copy and pasted too fast from a tutorial and overwritten the LUKS header from one of my drives with dd. The used command was: dd if=/dev/urandom of=/dev/sdb bs=512 seek=1 count=100 And now: ...
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How to mirror an NVME SSD onto another?

I'm not sure what the technical terms are for this, but I'm having the following problem: The internal SSD of my laptop died and set itself to readonly. It has all the recovery partitions and all that ...
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What's the difference between dd into a file and dd into a physical disk

The size "openwrt-19.07.6-x86-64-combined-squashfs.img" image is 20MB. If I change the file name to "openwrt.raw", I can import it into virt-manager and boot into the system. But ...
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How can I use the dd command to clone a USB drive?

I have created a USB with a Linux distro on it and would like to clone it to another USB drive. The drive with the distro on it is 256GB, the distro is on roughly 8GB partition of USB drive. The drive ...
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dd vs diskutil: which is faster when it comes to writing zeroes?

When I want to erase a disk, both dd and diskutil are viable options. To erase a disk with dd, I usually run something like dd if=/dev/zero of=/dev/$device bs=4096. The equivalent of this in diskutil ...
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Can I use dd with a mounted partition?

I would like to backup my /home (nvme0n1p3) partition to a backup.img file using dd. Can I do that while the partition is mounted?
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How to mount NTFS partition image in Windows created with dd on Linux?

As per the title, I need to work with an image created from Linux via ddrescue /dev/sda3 image.img in Windows. Notice that this is an image of a partition, not the entire drive. How can this be ...
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Why does a linux pipe slow my data transfer?

I noticed that if I use dd to move data from /dev/zero to /dev/null, I can max out around 6.1GB/s by adjusting the block size. dd if=/dev/zero of=/dev/null status=progress bs=512k count=2k # 2048+0 ...
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How to make a backup SDcard image when I can't find the device name using lsblk?

I've just installed Ubuntu and running with Windows 10. I've a linux SD card that is recognized as D: under windows, and I am able to mount in Ubuntu and access it's content using the following ...
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How to flash/write image to SD-Card using windows 10 command line?

I have a raw disk image .img file with multiple partitions (linux dd compatible) and want to flash it to a SD-Card. This should not require user interaction and not display a GUI (but some console ...
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SSD not working after cloning with dd

I was trying to clone a partition from my HDD hard drive to an SSD on another laptop. With dd I made a copy of the partition: dd if=/dev/sda3 of=/img.dd and then on the other laptop from a live cd I ...
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MacOS: Create a raw (dd) Image of an APFS volume

I have a .sparsebundle and I would like to convert it to something that can be used outside of the apple bubble. APFS/HFS is supported by a bunch of tools, but sadly the image formats are not from ...
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DD command speed

So the situation is: I've got an old Ipod 3g that's been jailbroken, and it's connected to my server, a windows machine, via ssh. The reason for that is that I want to make a copy of /dev/rdisk0 Ipod ...
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Debian - How to create an image file .img of your current system as a backup

I am new to Linux Embedded, and I am now trying to make sure I back up my system before making changes. I intend to use dd if=/dev/sdX of=/destinationPath/backup.img to create the image file and save ...
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Is there a way to use the “dd” command to transfer specific folders in an external hard drive?

I am currently trying to use dd to backup and copy the Backups.db folder (which contains all Time Machine Backups for Mac OS) in my external hard drive. The issue is that my hard drive does not only ...
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Cloned SSD, how can I clone it again?

I cloned my SSD A to a similar SSD B with a live system and dd. Now that backup got old and I want to save SSD A again to SSD B. My question is, how can I delete that cloned SSD B to make it writeable ...
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Is dd command in linux faster than single character reading functions

I need to extract some content of different length at different offset from a file. I would like to know whether to use dd command or simple character reading functions like fgetc
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Unable to format micro SD Card [duplicate]

I tried everything, including zeroing out first few sectors, using dd. But these operations have no effect whatsover. I am using Samsung micro SD to SD card adapter to connect to laptop card reader. ...
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Clone HDD with dd

I wanna clone a hdd but without loosing data from /home My current scheme is: [root@ns1 ~]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 512G 0 disk ...
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USB Flash Drive not recognized after unsafe eject while dd was running

Wasn't thinking I'm going to end up here. What happened? I wanted to benchmark the speeds of a USB flash drive, which was USB 2.0. My system is Debian bullseye/sid 5.8.7-1. I used the same method ...
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How to restore an entire Windows 10 installation using Linux disk images

I had created disk images of my Windows 10 installation using the dd command via a Ubuntu Live CD. The old hard disk size was of 2TB and I wanted to restore it to a fresh hard disk of the same size ...
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How much did dd destroy? [duplicate]

I used dd when I did a very dumb thing. Yes, I did override the wrong drive. I run dd if=file_on_sdb1.iso of=/dev/sdb1 conv=fsync. (Please note: /dev/sdb1/ and not /dev/sdb!) It didn't run completely. ...
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ubuntu/linux hardrive clone with dd issue with partitions and allocated side

I have a 500gb hardrive (sda) with 2 allocated partition (sda1 and sda2 which is the linux swap) (see image). I want to copy the data of 500gb hardrive to a 2tb hardrive named sdb. So I did dd if=/dev/...
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How to rescue USB drives?

A dd command on CentOS 7 failed, and now my USB disk (/dev/sdf) cannot be written to. These are the outputs I get: $ lsblk /dev/sdf lsblk: /dev/sdf: not a block device $ lsblk NAME MAJ:MIN ...
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How to trim a disk image? [duplicate]

I have a copy of my RPi's SD card made with dd if=/dev/mmblk0 of=backup.img. This creates a 32GB file. Only about 6GB of it is actually used, the rest is just data from deleted files. How would I ...
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Writing to /dev/sdX instead of /dev/sdX1

What happens physically if I want to copy some files to an external hard drive and do cp -a [file] /dev/sdX instead of cp -a [file] /dev/sdX1? Or when wiping a drive by overwriting it with zeros, is ...
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Can I safely clone an encrypted drive with dd without harming the data

I have a windows hard drive encrypted, using veracrypt, with AES HMAC-SHA-512, but from which the password was lost. Can I safely make a copy of this information bit by bit using something like dd? ...
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How to format `dd` speed units?

dd scales its reported speed (e.g. MB/s or kB/s), but I would like to enforce that it always use the same unit, e.g. B/s. How can I enforce that dd always prints the same units? Example usage: $ dd ...
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Why does disk read/write seem to half when running 2 dd processes on 4 different disks?

I'm trying to clone 2 external firewire disks on my debian fileserver using ddrescue. I'm running 2 processes in 2 terminals like so: sudo ddrescue -d -r3 /dev/sdx'/mnt/disk1/image1.img' '/mnt/disk1/...
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I accidentally made my laptop unbootable using dd [duplicate]

The story so far... I was experimenting with Unix's dd program on my Ubuntu laptop, trying to find a quick method to wipe a micro SD card securely. I set dd in motion, came back a few minutes later, ...
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674 views

Using Linux and dd to clone a FAT32 Windows partition to another, larger disk

PROBLEM: I currently have a 4GB disk with a single primary FAT32 partition that has Windows 98SE installed. The disk is almost full and I want to move the partition over to a larger 8GB disk. ...
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315 views

Copy partitions to emmc with correct offsets

I'm trying to populate an emmc in order to boot a custom Linux o.s. on an STM32MP1-based board. Here there is the schema of the partitions: TF-A copied in the two boot area partitions of e•MMC (...
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Prevent filesystem caching on tmpfs

Suppose that I want to put a big file (or a bunch of files) into a TMPFS, for whatever reason. Using dd with various combinations of direct and nocache flags, whether I copy a file from disk or create ...
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Deleting Files and directories on a Solid State Drive (fdisk, dd, rm)

I have been reading for a while on how rm, fdisk and dd work. I wasn't able to fully understand their source code however. Let's assume I would like to delete my /dev/nvme0n1p3 partition and the files ...
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190 views

What is limiting the LTO Tape write speed? How can I observe the ideal listed speeds?

I am testing out a new Quantum Ultrium 8 Tape and Drive. I see the listed maximum uncompressed and compressed data rate, respectively, are 360 MB/s and 900 MB/s. How can I observe/demonstrate this ...
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Debian: creating Windows 10 bootable install USB-drive using terminal (dd)

My goal is so simple, the title says it all, but every way I've tried, I've failed. I've read instructions on various sites (besides here) and they all seem to be missing something... this is what I ...
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1k views

How to convert dd partition image to virtualbox virtual disk?

I created a backup from /dev/sda1 and /dev/sda4 partitions using dd. but i did not create a backup from /dev/sda2 and /dev/sda3. How can I convert these 2 backup files from /dev/sda1 and /dev/sda4 ...
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Remove empty space from image backup of a drive

I used dd on a drive of mine that I am building my Linux distribution on. I have an issue, how do I prep that iso (of a 256GB drive (so I have a 256GB ISO image file)) to be of a smaller size (get rid ...

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