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Questions tagged [dd]

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

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Is that possible to get thin provisionning output using dd over ssh?

From : https://pve.proxmox.com/wiki/Migration_of_servers_to_Proxmox_VE dd if=/dev/sda | ssh root@proxmox dd of=/var/lib/vz/images/101/vm-101-disk-1.raw produce a raw image from original server and ...
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how can I run strings(1) or dd(1) on only the unused blocks of a partition

Subject says all. I have a sata disk from which I need to inspect only its unused blocks, i.e. blocks not used by files or dir entries. I want to run strings(1) on these blocks. Alternatively, I ...
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89 views

Copy LVM Volume Group to a new single hard disk

I have a headless Ubuntu (18.04) server with 3 hard drives each partitioned to a single lvm volume group for a combined size of 6Tb. I recently purchased a new hard drive that is 8Tb and I want to get ...
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Create a bootable VHD from a single Linux partition

I have a Linux partition on a physical drive. It uses EFI to boot. I would like to move this OS to Azure therefore I am trying to create a bootable VHD. I do not want to create a VHD of the whole ...
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24 views

Unable to write a compressed disk image using sg_dd and blocksize 520

I've got some disk images which are made from disks using 520 byte blocksize and gzipped using sg_dd if=/dev/sgX bs=520 | gzip -c image.gz It happily wrote the image to the gzip file, now I'm trying ...
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83 views

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, ...
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2answers
157 views

Unable to mount cloned partition via ddrescue

I have a problem with mounting the cloned partition. To clone it, I used as root: ddrescue -f -n /dev/sda3 ./sda3_rescue.img ./rescue.log The partition which I cloned, was a broken NTFS partition. ...
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115 views

Why does dd make the host unresponsive?

As root I yesterday did dd if=/dev/zero of=/var/lib/libvirt/images/dat.img bs=1G count=1000 and for many hours it made the server completely unresponsive. The raid controller is an HP P410 with 4 ...
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2answers
72 views

Bad Sector on disk causes the whole server to crash

Our dedicated server's hard disk was recently diagnosed with bad-sectors, and each time certain data on the disk are about to get accessed, the whole server goes non-responding before i i issue a ...
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1answer
148 views

dd “no space left on device” cloning SSD to USB drive

So I have a weird error, while dd'ing partition 3 (partition table below) from my laptop's SSD to a larger USB drive with an identical partition table. After writing ~3-4GB (expecting to write >75GB), ...
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1answer
2k views

HDD cloning with dd

I'm cloning a larger HDD(750GB) to a smaller SSD(250GB). I shrunk the partitions and there is only 83gb of used space. (I defragmented and did a chkdsk). Also, sum of partition sizes is smaller than ...
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337 views

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 ...
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2answers
173 views

Cloning multiple SATA drives using dd with the assistance of software RAID1

So, I clone lots of Windows-based NTFS drives from images each day and I'm halfway through a project that could potentially help me and others to speed up this process dramatically. I currently have ...
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1answer
80 views

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)...
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1answer
220 views

Initramfs error after image restore using dd

I need to create backups of a Ubuntu system in a way that I can easily restore the data and system as it is exactly in a ready to go state. So, I decided to go with dd to create a whole HHD images. I ...
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1answer
83 views

dmesg errors not showing in ddrescue

We had a disk in a raid go bad and we are suspicious another one might have minor errors. So to be safe we are trying to recover both disks using ddrescue. The various help pages recommend a two-to-...
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1answer
313 views

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 ...
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1answer
185 views

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 ...
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1answer
102 views

writing zfs dataset to block storage

Is there a proper way of writing a ZFS dataset, in my case which is an ext4 ubuntu filesystem, to a blank SSD? The data looks like this is that's at all helpful tank/filesystems/ubuntu_1604/(/etc, /...
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2answers
120 views

DD File Not Updating

I am following this thread to guide me from FreeNas VirtualBox to bhyve. https://blog.yuo.be/2017/01/04/migrating-a-vm-from-virtualbox-to-iohyve-bhyve-on-freenas-9-10/ However, I am stuck with this ...
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1answer
2k views

using dd with conv=sparse to punch zeros

I am attempting to clone a disk partition to an image file using dd. I want to create the image without zeros to minimize the filesize, and on the other hand I do not want to pipe through gzip. The ...
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1answer
5k views

PXE booting .IMG and .DD images

I have read many forum posts but still can't PXE boot image files. usb-image.dd is my image file. Instead of using USB sticks I would like to boot live Linux by using PXE. DEFAULT menu.c32 PROMPT 0 ...
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2answers
2k views

Backup and Restore Using dd and gzip

I've seen various posts discussing the use of dd for creating an image of a drive and only storing 'used data'. Before posing the problem/question, let's assume a few things. Assumptions The drive ...
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2answers
1k views

clone nvme drive with 4096 sector size to ssd with 512 sector size

I have an nvme drive with a logical and physical sector size of 4096. The block size of this drive as reported by blockdev --getbsz command to be 4096 as well. The destination drive is an SSD with a ...
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1answer
1k views

How to create a full backup of a remote ubuntu 16.04 server?

I just finished configuring a dedicated remote ubuntu server and want to create a backup with DD in order to be able to rebuild fast in case of hardware issues. The system has 2 SSD drives with 500GB ...
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1answer
704 views

Is it possible to clone raid member disks in an array with dd

I'm looking to expand the capacity of my qnap NAS by tripling the drive size from 2TBx8 to 6TBx8. However, I'm afraid the raid 5 will die before I can rebuild the array 8 times!! Can I remove and ...
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1answer
84 views

Two identical servers. One with extremely poor performance

I have these two servers with the following specs: OS: RHEL 6.3 Hardware: Dell PowerEdge R610, 12 cores, 64GB RAM Drives: 6 x Samsung 840 Pro SSD RAID controller: Intel RS25AB080, 1GB Cache RAID ...
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1answer
3k views

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 ...
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2answers
1k views

Does it involve network to copy a file within a NFS share? [closed]

I am assuming the following ways to copy a file with in a NFS share: Process 1: The client requests for the data to be copied from NFS share (if cache is not there) and the chunks of data are ...
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1answer
337 views

how to intentionally damage linux MBR (RHEL 7) on disk for test purpose?

I am running tests for MBR recovery on Red Hat Linux 7. I tried to intentionally erase the MBR with: dd if=/dev/random of=/dev/sda bs=1 count=512 I can see with fdisk -l /dev/sda that the ...
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1answer
270 views

How to use dd to dump an image to unallocated space

I have a bin file (chromiumos_image.bin) which contains some (around 12) partitions, which I need to dump into the unallocated space between 2 other partitions. The partition table is this: My ...
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3answers
640 views

How to mount the dd image of a swap file

I have several dd images from a single drive. One of them is the swap. I mounted all of the images in Ubuntu just fine except for the image of the swap. This is how the dd images break down: hda8 is /,...
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531 views

ZFS mirror migrated to other system with dd -> zpool import fails

I'm pretty new to ZFS and this might be an easy problem (but I don't find any discussions about how to do this): I've messed up a FreeBSD installation on a Root-on-ZFS mirrored ZFS Pool on a ...
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1answer
682 views

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 ...
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1answer
3k views

dd: zero-out all the remaining unused space of a drive

In the second answer of this question about disk cloning with 'dd', I read this command: dd if=/dev/zero of=/mnt/hdb/zero It is supposed to write '0' in the unused space of drive 'hdb', however I ...
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1answer
245 views

Using DD to produce an Image results in empty image [closed]

I am trying to take an image of my Android phone. Specifically I have tried to image the system and boot partitions. The imaging process appears to work correctly when using dd. However, when I ...
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496 views

Shrinking an img file that contains linux partitions

I've got an img file (4,02GB) containing a Linux OS. My goal is to shrink this img filed down to < 4GB. The img contains a linux partition that only holds about 2,5GB of data. I need to be able to ...
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1answer
478 views

Segmentation fault on dd command

I ran this command on Ubuntu to resize the /tmp and after that there is segmentation fault coming. dd if=/dev/zero of=/dev/xvda1 bs=1024M count=2 Its our live server. Is there any way to get it ...
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2answers
1k views

Acceptable I/O speeds for 6 x 250GB SSDs in RAID 10

I'm running CentOS 7 (XFS filesystem) on a dell server with a PERC H700 raid controller. Inside this server I have 6 x Samsung 850 Evo 250GB SSDs (yes they are consumer drives however, this is a home ...
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1answer
48 views

Backup old disk to external disk (new)

One of the 2 x 500GB drives on server is crashed can read but not write the data, which both are on Hardware RAID 0. So I connected an external 1TB new drive to backup the data and replace those 2 x ...
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1answer
406 views

File is too big for /dev/null

While testing a problem LUN for read errors, I encountered the following problem: find /mnt/problem_lun/ -type f -print -exec dd if={} of=/dev/null bs=8k \; ... /mnt/problem_lun/a_file dd: writing `/...
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3answers
2k views

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 ...
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2answers
3k views

How to execute bash script through pxe boot [closed]

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 ...
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1answer
909 views

Create random file with openssl [closed]

So I read this questionUrandom Alternative, but I am unable to make a comment there (without 50 rep) - therefore I open a separate question: If I use this command instead of dd and urandom, how do I ...
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2answers
366 views

Reduce xen image disk usage

Two cases: 1.If making hdd image using dd and copy it trough nfs to another server: mount -o ro,remount / dd if=/dev/sda bs=64K | gzip -c > /share/test.img.gz then after gunzip I get 20Gb (for ...
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1answer
140 views

dd vs. dd pipelined: which is better? [closed]

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: ...
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1answer
886 views

Make a dd image restorable to a smaller drive

Suppose I have a 32 GB USB flash drive (UFD) and an 8 GB UFD. I have a 5 GB partition at the start of the bigger UFD, and the rest is unallocated. The problem is to copy the partition and boot sector ...
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1answer
307 views

Copy LVM volume group spanning two physical volumes on two disks

[update] i have copied the two primary partitions using gparted. now i am stuck trying to copy a single volume because it is made of two physical volumes each on separate disk...ideas? /sda5, /sdb1 = ...
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1answer
65 views

The best way to copy OS on RAID10 and lvm partition

I need to backup/clone the entire operating system. The problem is it's 2TB of data on lvm partition and RAID10 (i do not know is it dedicated controller or fake RAID in BIOS. Probably the second ...
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1answer
121 views

Deleted MBR on virtual machine on purpose, but entries are preserved

I'm playing with Master boot record. I decided to delete and restore it on my vmware machine. With Ubuntu LiveCD I'm trying to erase partition entries and signature with command: dd if=/dev/zero of=/...