2y ago

usb formatting

shamelessly stolen from nixCraft on mastodon

53 comments

Your USB is probably named '/' or '~' so give that a go.

When you hit enter on the DD command, and your main storage light suddenly starts flashing.
- When you hit enter on the DD command, and your eyes suddenly start flashing.
  
  Little Jimmy wanted to try Fedora, But little Jimmy is no more. For what he thought was his external drive, was actually his cerebral core
  
  https://www.youtube.com/watch?v=ajW2fDy41fY
- So? I'm just creating an 8 GiB swap file.
  
  Try btrfs, where with only 5 hours of research you can create a swap file without writing the entire file.
  Also there is no other option, the 5h are non-optional.
  After doing that twice, In my / now lives
  ::: spoiler /swapfile-howto
  undefined
  
  # this is btrfs not a normal file system. # We have to create and allocate the file in a btrfs friendly way, # and tell btrfs to not move or segment it. touch /swapfile999 chmod 600 /swapfile999 truncate -s 0 /swapfile999 chattr +C /swapfile999 fallocate -l 999G /swapfile999 mkswap /swapfile999 swapon /swapfile999 -p 200
  :::

You used something called disk destroyer, and you just found out why
- Disk Duplicator is a destroyer? Man, I used to image so many drives with DD back in my helpdesk days…
  
  dd does not stand for "disk duplicator". That's a modern backronymization that doesn't reflect the original general usage of the command which is to "convert and copy". Efficiently (with respect to I/O) copying raw data is only one of its intended purposes; it also converts text encodings.

Obligatory useless use of dd comment.
- That was an interesting read, thank you!
- I haven't touched dd since I read that about a year ago, super interesting!
  For people that use dd because they like the progress bar, I highly recommend pv.
- Except the proposed alternative should not be cp or pv, but dd bs=4M oflag=direct,sync status=progress.
  I feel like I'm taking crazy pills with all the advice in this thread, because for USB keys you will otherwise end up instantly filling the write cache... which will block the apparent progress of the copy operation (so why even use pv since all you're doing is measuring your RAM speed and available cache size) as well as heavily slow down (even potentially partially freeze in some circumstances) the rest of your system as the kernel is running out of free pages and can't flush caches fast enough due to the slow-ass write speeds of usb keys.
  (Alternatively there is a kernel setting somewhere to disable caching globally for a block device... but in most cases caching is good, just not when you're flashing an ISO).
  
  so why even use pv since all you're doing is measuring your RAM speed and available cache size
  This is probably why pv progress fills in a second but is only done after a few minutes. Nonetheless, shell redirect, cat, cp work fine and handle blocksize and cache dynamically.
  Your worst case scenario never happened to me after years of using pv/cp for flashing sticks/overwriting/copying partitions, even with some ...risky mount settings. Honestly doesn't make much sense to me either. Again, dd isn't some sort of magical safe handle to make the process progress smoothly. Like i use to say, dd is a skalpell, not a shovel.
- It was less useless for that purpose when cp and cat were less I/O efficient compared to dd with the appropriate block size, which isn't as much the case now as it used to be.

Another advantage of having a NVMe SSD, hard to confuse /dev/nvme0n1p2 with /dev/sda1
- It's even easier to prevent confusion if you use /dev/disk/by-id/ id's, it only took a few times of overwriting the wrong disk to figure that out.
  
  I think that does the opposite for me lol
  
  How can I figure out which direct device is associated with a specific id?
  
  When I accidentally decimated my external hard drive, it had NTFS cause there were a few windows machines I would plug it in. Then I reformatted the disk but then I thought to myself, should I have another partition for my Linux machine because that drive gets corrupted and then I need to plug to a Windows machine to repair it once in a while. Then I created an ext4 partition on the disk. Then a few days after I shrinked the NTFS partition and extended the ext4 to the whole disk. Now that disk only has one partition called sda2. Which is kinda weird but makes it easier to distinguish from others disks on the system.
- I just make use of my paranoia, so I triple and quadruple check. Then get a coffee and quadruple check again. Never messed up once
- Even if it's similar names I'd normally plug in USB, do dmesg, then issue a command with latest device name.