0
votes
3answers
100 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 ...
4
votes
1answer
233 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 ...
1
vote
3answers
276 views

Full DD copy from hdd to hdd

UPDATE: 2 This seems a lot better than before (Thanks to Groxxda for the suggestions): sudo dd if=/dev/sdb bs=128K | pv -s 3000G | sudo dd of=/dev/sdc bs=128K ETA is about 9 hours for 3TB, whereas ...
2
votes
3answers
117 views

Why is dd running forever on a 8 GB drive

I have a filesystem handled by ZFS and it's about 8 GB. I tried to zero out the filesystem by running: dd if=/dev/zero of=/EMPTY bs=1M | true rm -f /EMPTY And normally on an ext4 filesystem, it ...
1
vote
3answers
411 views

1:1 copy with dd

I need to get a copy of an HDD that is a real 1:1, I mean not just the filesystem but also the geometry and the partition table and everything in between. if I'll just use dd if=/dev/sdb ...
3
votes
1answer
1k 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 ...
4
votes
3answers
107 views

Can I overwrite LUKS partition with it's decrypted content?

I have HDD with my data (partial backup of most important data available on other HDD), currently it's formatted as Ext4 over LVM over LUKS. I want to remove LUKS layer, but reformatting and data ...
1
vote
2answers
91 views

Debian: Create compressed Harddrive for copy

On my Debian system I have a box with certain configuration settings that I like but I've had to change them continuously. There have been times that I've gotten into a some-what irreversible ...
1
vote
1answer
34 views

Backup 'empty' parts of disk drive

I have a USB drive which has around 7MB of 'empty' space at its beginning. The first partition in MBR starts at 8225kB, according to Parted. How can I back up this space using something like dd? ...
1
vote
1answer
127 views

Filesystem not showing correct size in Mac OSX

I installed a new HDD and transferred my old data to it by using dd on my old HDD and then dd again to the new HDD. However, when booting from the new HDD, it does not recognize the new, larger disk ...
1
vote
2answers
258 views

Hard disk drive disappeared

Yesterday I performed a hard-reset while Linux was booting. This led to a hard issue with the HDD (UNC while recovering journal). I had to use ddrescue instead of dd because dd crashed on I/O error. ...
7
votes
4answers
321 views

Protecting Devices from dd and fdisk Commands

I'm wondering if there is some way to prevent certain certain devices from becoming the output file of the dd command and the target of the fdisk command. I'm currently using the two operations to set ...
3
votes
2answers
289 views

Is it safe to only partially restore a disk image with dd?

I have saved my whole hard-disk with dd to an image file. The hard-disk contained some primary partitions formatted with ntfs, swap and ext4. I did it this way: dd if=/dev/sda | ssh user@fastmachine ...
4
votes
1answer
106 views

Error(?) in output of the dd command

When I run the following command: dd if=/dev/sda of=output bs=512 count=1 In the middle of the output, I see this text: GRUB ^@Geom^@Hard Disk^@Read^@ Error^M What does it mean?
1
vote
2answers
610 views

Writing data on particular sectors or blocks

Not sure if it's better suited for superuser of serverfault boards, let me know. I have a drive which I repartitioned with fdisk. Initially there was only one big partition, now there are a number ...
2
votes
1answer
2k views

VBoxManage: Error: Can't be used as the requested device

I used the soluton from this thread but always i get VirtualBox error: The medium 'lvol.vmdk' can't be used as the requested device type (0x80004005) I've tried all controllers SATA, SCSI, IDE and ...
4
votes
1answer
2k views

What's faster, dd 1.5TB or rsync 500GB?

I need to save data from a failing hard drive. Sounds like ddrescue or myrescue (or maybe clonezilla?) will be my best friends here, but I'm just wondering what will likely be faster: using ...
3
votes
1answer
2k views

What is the fastest way to write all sectors on a drive?

The goal in my case is not to securely erase data, but simply to force sector reallocation by the drives firmware. I have a drive that has had a few file corruptions. It seems to be due to getting ...
3
votes
4answers
2k views

Comparison of raw block devices

Is there a utility (or some shell magic) that allows me to compare two block devices? Details: I have one large (0.5 TB) RAID device that I've backed up to a slightly larger SATA device using dd. ...
2
votes
3answers
445 views

Duplicating a hard disk

I'd like to simply duplicate a hard disk drive to another hard disk drive of the same size. I know I can simply do: dd if=/dev/sda of=/dev/sdb (or whatever the names of the drives are in /dev). ...
50
votes
8answers
26k 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 ...
11
votes
3answers
944 views

saving data from a failing drive

An external 3½" HDD seems to be in danger of failing — it's making ticking sounds when idle. I've acquired a replacement drive, and want to know the best strategy to get the data off of the dubious ...