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Questions tagged [dd]

This command is used to do low level copying of data.

Convert and copy a file, write disk headers, boot records, create a boot floppy. dd can make an exact clone of an (unmounted) disk, this will include all blank space so the output destination must be at least as large as the input.

For more info refer to the manpage.

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Recovering deleted plain text (emails) files from raw disk image

I'm hosting my own linux mail server for my family. Yesterday my father lost all the mails in his Inbox folder. I'm still not sure whether it's due to a terrible user error or compromised password, but that's not the point here. Thanks to Murphy's…
piwai
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DCFLDD and a Hex Editor

I sometimes use dcfldd, because it has more features and is easier to use than regular dd. It gives a constant status and updates it fast, and it also has pattern input which is a lot faster than reading from /dev/zero or any other device. As an…
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Is it faster to wipe out multiple hard disks with dd=/dev/zero simultaneously?

I have 3 hard disks 1T each. I want to wipe them out completely. I decided yo use dd like so: dd if=/dev/zero of=/dev/sdb bs=1M dd if=/dev/zero of=/dev/sdc bs=1M dd if=/dev/zero of=/dev/sdd bs=1M Since it takes a while for the commands to complete,…
Pavel Tankov
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Find out exact location of GRUB / GRUB not working after copying disk image

I prepared an Ubuntu server image with VirtualBox. To transfer the image to the server's SSD I first dded the MBR (512 bytes) and then the LVM partition (PV containing the root partition shrunk to 3GB). The server failed to boot because some parts…
code_onkel
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dd using all memory and swap

I have a dedicated Centos 6.9 linux server with a company that crashed due to hardware failure and has been restored with the old HDD's on a usb caddy. I am trying to move lvm partitions over to the new internal hard disks. I have created a new…
williame
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I mistakenly `dd if=/floppy-image of=/dev/sda` and erased my entire partition

I think I have just made the worst mistake one can made - please help me recovering from it. A guy from another room came over said to me this is a BIOS update (or something similar) for the new servers we just bought. Would you mind making an image…
Tzury Bar Yochay
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dd's relation with page cache

The free command output of my server is currently like below: # free -m total used free shared buffers cached Mem: 995 780 205 0 49 599 -/+ buffers/cache: …
Jepsenwan
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Repair FAT filesystem on image

I've got a USB pen drive with a corrupted FAT filesystem. Now I try to repair it. So to first try what I can get from it without endangering the original hardware further, I've created an image with dd using the following command line: $ sudo dd…
white_gecko
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Installing CentOS on HP Server, SSDs connected to a RAID controller

I am trying to install centOS 6.0 in this HP Server, I contacted with the support and they said me that it supports that OS. I have no problem installing it on a SSD that is connected directly to the motherboard, but if I connect it to the raid…
yb_esc
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Truncate empy space from a raw dd image

I have a raw disk image I took using dd of a Ubuntu instance. The total disk size is 300 GB, but only 5.5 GB used. Is there a way to resize the raw dd image down to 20 GB, keeping all of the 5.5 GB of data, and just truncating empty blocks?
Justin
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How to execute bash script through pxe boot

Can any one tell me how to execute bash scripts via pxe boot. What I am trying to do is when Raw Server boots up I want to deploy cloned image over hard disk via PXE boot. I am aware that there are some tools like Fog which does similar thing. But I…
Kapil
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dd vs. dd pipelined: which is better?

Here I read, in the comments, that a guy got more performance when used dd in pipeline for a copy. Like for example: dd if=in | dd of=out instead of dd if=in of=out Is it really faster? Why? Also: he talked about symmetric and asymmetric copying.…
sl34x
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Slow IO Performance with PERC H700/710 with current linux distributions

we noticed really bad write performance, on our new Dell R720 with Perc 710. Especially when it come to writing a lot of small files. The funny thing is that this bad performance only occurs on newer linux distributions like ubuntu 14.04. or latest…
noe
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Create a VHD file from a Linux disk

I have a disk containing CentOS 5.8 that was removed from a dead box. I would like to make a VHD file from this disk so I can run a virtual machine (instead of a new physical machine). The Virtual Machine host is a Windows 2008 Server running VM…
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How to clone a RAID5 system

I clone single disk systems by booting the master system to a CD and running… dd if=/dev/sda | gzip - | ssh user@hostname dd of=image.gz Then I boot the target system with the CD and run… ssh user@hostname dd if=image.gz | unzip - | dd…
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