You could use a higher block size value to increase speed.
And yes, dd doesn't care about filesystems at all.
If you want a good ftp backup tool based on dd, give g4u a try http://www.feyrer.de/g4u/

"status=progress" is a super useful option to add to the end of the 'dd' command (exactly like that, no '-' or '--'.) It's a fairly recent addition so won't work in super old distros or Mac OSX/BSD.

For example: dd if=/dev/sdx of=image.img bs=128k status=progress
(Note that I'm not piping into gzip, so it won't compress the image.)

I usually use bs=1M or bs=4M but it doesn't make a huge difference over a certain threshold.

It makes a big difference if there are bad sectors, since a single bad sector will cause the entire block containing it to be discarded/zeroed in the image.

In that case, maybe dd-rescue is more what you want.

I had no idea about the status parameter though. I always opened another console and used "ps -a | grep dd; watch -n30 kill -USR1 <pid>"

SirNickity wrote on 2020-02-14, 22:43:

In that case, maybe dd-rescue is more what you want.

I had no idea about the status parameter though. I always opened another console and used "ps -a | grep dd; watch -n30 kill -USR1 <pid>"

I really miss status=progress when I'm running Solaris or BSD.

jmarsh wrote on 2020-02-14, 20:26:

It makes a big difference if there are bad sectors, since a single bad sector will cause the entire block containing it to be discarded/zeroed in the image.

If there is bad sectors, you will have a hard time reading the data anyway. Like they say... Real men do no backup's, they cry instead.

Morale of the story... Just do backup anyway. I look at DD as a tool for cloning a fresh install. The option to keep copying if there is bad sectors, are only used, because it will be a waste of time if you get to like 95/98 percent cloning of a one terrabyte drive.

SpinRite is a good tool for fixing bad sectors, especially on old/retro drives. It is not freeware, it costs $90, but once you buy it, you can use it on however many drives you want for the rest of your life. It is a DOS utility and must be run from native DOS, but it is very good at finding and fixing bad sectors if the drive is not already near-death. I've used it to make a dying drive readable "one last time" to get the data off. It is also a good maintenance tool. Run it on Level 4 once a year or so on your old drives to revive weak sectors and keep them from going bad.

Once you're in the realm of terabytes, try 'cat' instead.

I'd use clonezilla to do disk imaging if your computer supports it (and I'd try older versions if modern ones are not supported). Clonezilla will try to copy only data used in filesystems (using less space), have more compression options (again, less space) and it can resize the filesystems if you need to restore your image in bigger disks (I haven't had any success trying to restore into smaller disks even if actual data fit into them). Keep in mind that some filesystems store information about the physical disk layout and can not be directly used on disks with other layouts.

The only real advantages of dd are that works in any Unix ( but will stall or crash if it founds data errors) and that you can mount your image and extract files (but that advantage can be lost using gzip, I don't know if compressed images can be mounted directly). If your disk is not healthy, I'd use dd-rescue without gzip to copy it (and then, you can use ddrutils to check what files were related to bad blocks). Also, if you're using Linux, I'd try to use bzip2 instead of gzip to compress your image and save some space.

Just to group like-with-like,

1] These days, typical linux desktops also let you img easily from the GUI. Attached below is a capture from gnome-disks-utility. (Shown in Mint, which is derived from Ubuntu, which is derived from Debian...)

2] For SATA drives I have this Inatech USB3.0 dock / cloning -station. It's been absolutely great. Deserves all the 5-stars people give it. I mostly use it to do badblocks and grsync backups via USB3.0 on a retired laptop. Buti it's also a stand-alone cloning station. Which is great for my gameboxes, and also for making offsite copies of my main backup.

It doesn't do anything I wasn't already doing with semi-retired 'utility' computers. But it does take up less space, and it works very well. I'm glad I picked one up.

Zup wrote on 2020-02-16, 18:21:

I'd use clonezilla to do disk imaging if your computer supports it (and I'd try older versions if modern ones are not supported).

For Win9x, you need Clonezilla 1.1.0-8 and Gparted 0.3.7-7. See Re: Utility for making exact hard drive clones?

Not strictly "Linux only" -- I've used dd for Windows to clone/image hard drives and CF cards.

It's a little tricky to come up with the correct device name to get the most complete image possible (e.g. MBR and partitions). You gotta run "dd.exe --list" as administrator and do a bit of trial-and-error with the different "\\?\Device\" names for your disk.

However, Clonezilla is indeed a more comprehensive tool and I can endorse it as well.