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

learn more… | top users | synonyms

3
votes
2answers
1k views

Raw copy with sector precision on windows

Is there some program for windows that is able to do what dd does in linux out of the box? I need to copy from a file to a physical disk in raw mode where I need to define offsets for input and output....
152
votes
26answers
298k views

Using DD for disk cloning

There's been a number of questions regarding disk cloning tools and dd has been suggested at least once. I've already considered using dd myself, mainly because ease of use, and that it's readily ...
-1
votes
1answer
36 views

Disk image growing in size [closed]

I am trying to set up Rasberry pi for jobs that don't deserve bigger machine. I downloaded a Pidora disk image (.img) zipped it is roughly 512MB. After unzipping it is 2.2GB ( no problem here). ...
-1
votes
2answers
98 views

HHD cloning with dd on running server

Is it possible to clone HDD with dd command on linux while server is up and running. Server running, Apache, MySql, NGINX. I ask this coz won't have downtime.
0
votes
1answer
131 views

When copying VM filesystem over netcat, dd copies double the disk size

I'm attempting to copy the disk of a working headless virtualbox VM (VM1) on one server to a new VM (VM2) on a vCloud server. I don't have access to the host of VM2. The OS is Windows Server 2003 (32-...
3
votes
0answers
2k views

Cloning a bitlocker encrypted disk

Our company's had its laptops for just over 2 years now and they have all become slow and many of them have had their harddisks dying randomly lately. I noticed that many of my colleagues use a tilted ...
-1
votes
1answer
105 views

Fixing partition table after writing 0s to beginning

I have a sw raid10 setup like: /dev/sdX > partition /dev/sdX1 > raid md0 > lvm > fs. I'm an idiot, and wrote 4gb of 0s to /dev/md0 with dd dd if=/dev/zero of=/dev/md0 bs=4k count=1000000 conv=...
-2
votes
3answers
70 views

Using dd for backup with a single disk

I have a RHEL5 Amazon cloud instance that I need to image to another instance in order to setup a test environment for some upcoming patching I'm doing. The server to be imaged is a production server. ...
0
votes
1answer
130 views

dd or cat - overload when read /dev/zero

I need reclamation thin disk, so Im trying fill zero on vhdd. But when I run it, so server is overload with 20k IOPS and full satured SAN network. Can you help me how I can slow b/w for this? E.g 10MB/...
1
vote
2answers
907 views

cloning with dd - is non-partitioned space considered the same as empty space within filesystem for resulting image size?

note: all = all that i've found all the "cloning with dd" information talks about how dd copies all the "empty space", but literally all writings seem to be responding to a situation where ...
1
vote
1answer
78 views

Anyone tried dd'ing Raidmembers?

I want replace all disks in a 10 disk raid6 (linux software raid). I could do this by pulling a disk, let the array rebuild, rinse, repeat. But this would take a very long time, and cause 10 ...
3
votes
1answer
805 views

Large write with dd fail on RAID-5

I have a server with a RAID controller which connects to a JBOD over SAS. JBOD is populated with 16 SAS-HDDs of 3TB (8 of one make and 8 of other, same rpm). I have configured 3 logical drives with ...
4
votes
1answer
1k views

Linux page cache slows down IO on dual cpu server with 64GB ram

I have a massive problem with the linux page cache which slows down the IO. For instance if I copy a lvm partition with dd, linux cache the data in the buffers or caches (free –m). That is not the ...
0
votes
1answer
79 views

handle multiple calls of rsync, dd and snapshot

The server runs the following operations often. It takes a snapshot of a logical volume, then backup up the content to the remote backup server. It is possible that multiple backups and transfer ...
2
votes
1answer
3k views

dd command piped over gzip and ssh faster and faster as dd progresses

I am running the following command to copy a LVM from one host to another: dd if=/dev/vg_1/lv1 conv=noerror,sync bs=4M | gzip | ssh user@ip 'gzip -d | dd of=/dev/vg_2/lv1 bs=4M' To begin with I was ...
0
votes
1answer
267 views

dd output file larger than input file when executed with conv=noerror,sync

I am trying to backup an LVM on one of my servers with the following command: dd bs=4M conv=noerror,sync if=/dev/vg_volgroup/LvmName | ssh myuer@myip "dd of=/home/myuser/LvmName bs=4M conv=noerror,...
0
votes
1answer
537 views

dd unable to write to tape drive

I'm trying to dump our online backups to tape; for obvious reasons I want to encrypt the data on the tapes, so to write to the tape I need to tar everything up, pipe that to openssl to encrypt it, ...
1
vote
0answers
190 views

How to restore a dd image to an EBS volume

I have a local dd image myimage.bin, which I want to use to create an AWS EBS volume. The only way I can figure out how to do this is to, 1) Launch an AWS instance 2) Create and attach an EBS ...
1
vote
1answer
312 views

Does 'lvremove' destroy data?

I assign a LV for each vm guest. When deleting a vm, I remove the corresponding lv running 'lvremove'. But is it necessary to destroy the data before running 'lvremove'? Does lvremove do the work of ...
2
votes
2answers
150 views

DD over SSH from Server to Server

Is it possible to DD one server to another? Maybe through SSH? I've looked around and I have seen examples of DD using SSH from local to server and vice versa, but is it possible to do it from server ...
1
vote
2answers
1k views

Why does dd show slow disk speed first time?

I'm checking the disk speed of a hdd on CentOS 6 using dd command. The setup is a DRBD setup - with this server being primary. To ensure that I get correct values, I execute the dd command 3 times ...
0
votes
1answer
96 views

rsync, dd and then add to RAID 1, could cause database corrupted?

Firstly I have a HDD which has been setup as RAID, type Volume, not RAID 0 or RAID 1 ... and I wanna add one more HDD to setup a RAID 1 array. These bellow steps are what I've done. Detach from ...
3
votes
3answers
237 views

LVM: Using an image of a PV?

I have a logical volume spanning several drives. One of those drives (3TB, the largest of the bunch) is dying, and I am currently making an image of it (via ddrescue). I'm not yet sure on how to use ...
0
votes
1answer
190 views

Correct way to copy vm disk

I have a VM’s disk to copy from one host to another for live migration. I can think of two ways to copy the VM’s disk. Do a snapshot of the Logical Volume in the original host, create a Logical ...
0
votes
1answer
164 views

Use dd or redirection to write to tape?

My Googling for writing to tapes with encryption have turned up various results. Most along the lines of piping tar to openssl similar to: tar cf - /home | openssl des3 -salt -k "Your-Password-Here" ...
4
votes
1answer
1k views

Using dd on disks with different sector sizes

I would like to move a partition to a new drive. The old drive has a sector size of 512 bytes while the new one has a sector size of 4096 bytes. I tried doing a dd of the full disk, but that failed ...
-1
votes
1answer
943 views

Benchmarking GlusterFS & NFS on AWS using iozone and dd gives different results

I have tried benchmarking GlusterFS vs NFS on Amazon Web Services (AWS) using a m1.medium sized EC2 instance. We use the AWS EBS as the block store, with a XFS file system. Running Ubuntu 12.04 ...
4
votes
2answers
521 views

Save data after accidental dd format

as embarrassing as it sounds I managed to dd a debian iso to an external hd instead of my usb pen drive. now my 1.5 tb western digital has 1 700mb partition named debian and the rest is unallocated ...
3
votes
3answers
1k views

Creating an iso file in Linux

I have created iso files by using two commands: dd if=/dev/cdrom of=filename cp /dev/cdrom filename What's the difference between the two, both have worked for me.
1
vote
1answer
328 views

How to move partitions from 2 LVM volumes into one LVM on other disk?

i had 2 partitions with following layout Disk /dev/xvda: 376.4 GB, 376354897920 bytes 255 heads, 63 sectors/track, 45755 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (...
1
vote
1answer
516 views

DD broke my whole partition - boot failed: not a bootable disk . Any way to recover it?

Im kind of freaking out here, if anyone can help me please help me... This happened to a Windows 2012 KVM virtual machine. I had a very important database running in it, if I could only recover that ...
1
vote
0answers
1k views

Differences between hdparm --read-sector and dd with “Current Pending Sectors”

This was originally an "answer" to How to use hdparm to fix a pending sector? I'd been getting SMART notifications for the same "Current Pending Sector" for days. The dd solutions around weren't ...
0
votes
2answers
248 views

Cancel /dev/zero before it finishes?

To clear a large hard drive I was using dd if=/dev/zero of=/dev/sda. Only later I realized from reading more sources that the default block size is 512, and if I want the process to go quicker I ...
1
vote
1answer
353 views

Why is my synchronized I/O so bad compared to direct?

I have two 3TB disks in a software RAID 1 setup and the host OS is 64bit Debian wheezy. Issuing: dd if=/dev/zero of=test bs=64k count=3k oflag=direct && rm test Yields: 201326592 bytes (...
0
votes
1answer
379 views

1. XFS: how to find path / directory of inodes 2. XFS in a file -o loop and ddrescue?

how to find the full original file/directory path of some damaged XFS inodes? and how to list the last modified few 10000 inodes (=edited or moved files/directories) rapidly among millions of ...
1
vote
1answer
272 views

Server crash when creating a swapfile on a running machine (CentOS Linux)

I created a swap file with root on a running server, using swapfile creation guides which I found on the net (http://blog.serverbuddies.com/adding-additional-swap-space-to-your-linux-server/m Create ...
5
votes
2answers
5k views

Why is Clonezilla faster than dd?

On my SSD imaging (Source and Destination are 2 SSDs) I get 12GBpm using CloneZilla while with dd I get only 5GBpm. What makes Clonezilla so much faster than dd?
2
votes
5answers
5k views

Creating a 80GB image with dd on a FAT32 drive

I have a question concerning the creation of an drive image with dd. Normally i would simply type: "dd if=/dev/foo of=/dev/bar". But in this case i only have a fat32 formatted drive at hand, which ...
5
votes
1answer
729 views

Experiences with using `dd` to copy multi-partition, multi-FS device

I have a disc with several partitions on, each of which has a different kind of file system (ext3, ext4, and, let's say, NTFS). I want to know if I can copy the whole disc to a new one (which is of ...
1
vote
1answer
837 views

Operating System not found when loading DD image in VMware

I provide much details below to hopefully make my issue as clear as possible. Using dd if=/dev/ps3da2 of=/mnt/edexhdd/EDPS3LINUX.iso bs=16384 I copied a fairly huge partition from a physical Linux ...
4
votes
1answer
733 views

Backup root partition with dd without downtime

Is there a way to remount / as read-only and buffer new writes in RAM, so can backup the / media with dd? I want to create a bootable image from my SoHo-Server (Debian 6) without a live cd or any ...
1
vote
2answers
829 views

Large delay starting “dd” write in background in bash even when using nohup

I wrote a small script to print the memory usage during a large sequential write of a file. #!/bin/bash rm result echo 3 > /proc/sys/vm/drop_caches sync; echo start nohup time dd if=/dev/zero of=...
4
votes
3answers
1k views

Recovering with DDRescue Cannot Complete (write error: Read-only file system)

I'm trying to recover a corrupt VDI using vdfuse to mount the VDI and using dd_rescue to rescue the borked partition. dd_rescue seems to be working fine but once it reached about half of the ...
0
votes
2answers
1k views

Clone Flash Drive in Linux using DD

dd if=/dev/sda of=/dev/sdb I want to create a clone a bootable USB stick. lets say sda is 2GB sdb is 32GB. The above line will create a replica but the usable size will be 2GB. How can I use the ...
1
vote
0answers
322 views

Backing up VMs to a tape drive

I've got myself one of these fancy tape drives, HP LTO2 with 200/400 GB cartridges. The st driver reports it like this: scsi 1:0:0:0: Sequential-Access HP Ultrium 2-SCSI T65D I can ...
-1
votes
1answer
147 views

Cloning my hard drive as a backup [closed]

At the moment, I have an Ubuntu 11.04 installation on a single 500GB hard drive in my laptop. The hard drive is partitioned into four parts: 500MB for the boot information, 2GB for the swap partition,...
0
votes
1answer
658 views

Drive cloning dd or rsync/sync via KVM

I've got a crash and the system won't boot correctly. I am getting errors like: ata3.00: status: { DRDY } ata3.00: status: { UNC } What would be the best way to save the main drive to make the ...
0
votes
2answers
376 views

Using dd command and running out of space while cloning drive to img

I have a problem with drive cloning. Im using dd on damaged disk with bad sectors trying to make an image from it. Im booting computer with Live Linux CD . Damaged disk: sda 146GB (NTFS) External ...
5
votes
2answers
5k views

Mounting a linux image built with “dd” on Mac OSX 10.7 [closed]

I recently did a ssh root@myserver "dd if=/dev/xvda " | dd of=/<localpath>/myimage.img as instructed by my VPS server docs at linode. I did this before to another linux system and mounted it ...
19
votes
3answers
3k views

Securely wipe an entire Linux server with itself

I have remote ssh access and root access. I do not have physical access. I'm not looking for solutions involving booting into anything, I want to do this from what is currently running. OS is SL6. ...