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Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).

Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.

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What is the largest file transfer you have ever done? (startrek.website)

submitted 3 months ago by [email protected] to c/[email protected]

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I'm writing a program that wraps around dd to try and warn you if you are doing anything stupid. I have thus been giving the man page a good read. While doing this, I noticed that dd supported all the way up to Quettabytes, a unit orders of magnitude larger than all the data on the entire internet.

This has caused me to wonder what the largest storage operation you guys have done. I've taken a couple images of hard drives that were a single terabyte large, but I was wondering if the sysadmins among you have had to do something with e.g a giant RAID 10 array.

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[–] [email protected] 3 points 3 months ago (4 children)

Why would dd have a limit on the amount of data it can copy, afaik dd doesn't check not does anything fancy, if it can copy one bit it can copy infinite.

Even if it did any sort of validation, if it can do anything larger than RAM it needs to be able to do it in chunks.

[–] [email protected] 3 points 3 months ago

No, it can't copy infinite bits, because it has to store the current address somewhere. If they implement unbounded integers for this, they are still limited by your RAM, as that number can't infinitely grow without infinite memory.

[–] nik9000 2 points 3 months ago

Not looking at the man page, but I expect you can limit it if you want and the parser for the parameter knows about these names. If it were me it'd be one parser for byte size values and it'd work for chunk size and limit and sync interval and whatever else dd does.

Also probably limited by the size of the number tracking. I think dd reports the number of bytes copied at the end even in unlimited mode.

[–] [email protected] 1 points 3 months ago

It’s less about dd’s limits and more laughs the fact that it supports units that might take decades or more for us to read a unit that size.

[–] [email protected] 0 points 3 months ago

Well they do nickname it disk destroyer, so if it was unlimited and someone messed it up, it could delete the entire simulation that we live in. So its for our own good really.