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    Dumb question - linux dd write 0s to multiples disks at once

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    linuxddcommand line
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    • DustinB3403D
      DustinB3403
      last edited by

      Bash command not found

      Is that not an option with pre installation using a bootable USB?

      1 Reply Last reply Reply Quote 0
      • travisdh1T
        travisdh1 @DustinB3403
        last edited by travisdh1

        @dustinb3403 said in Dumb question - linux dd write 0s to multiples disks at once:

        @scottalanmiller said in Dumb question - linux dd write 0s to multiples disks at once:

        With a single command, no. But you can run several commands at once.

        That would suffice, what would it look like?

        tack a ; to the end of each dd command and put them all on a single line

        dd if=/dev/zero of=/dev/sda bs=4k; dd if=dev/zero of=/dev/sdb bs=4k
        
        DustinB3403D 1 Reply Last reply Reply Quote 1
        • DustinB3403D
          DustinB3403 @travisdh1
          last edited by

          @travisdh1 said in Dumb question - linux dd write 0s to multiples disks at once:

          @dustinb3403 said in Dumb question - linux dd write 0s to multiples disks at once:

          @scottalanmiller said in Dumb question - linux dd write 0s to multiples disks at once:

          With a single command, no. But you can run several commands at once.

          That would suffice, what would it look like?

          tack a ; to the end of each dd command and put them all on a single line

          as

          dd if=/dev/zero of=/dev/sdb bs=4k; dd if=/dev/zero of=/dev/sdc bs=4k; dd if=/dev/zero of=/dev/sdd bs=4k; dd if=/dev/zero of=/dev/sde bs=4k

          right?

          travisdh1T scottalanmillerS 2 Replies Last reply Reply Quote 1
          • travisdh1T
            travisdh1 @DustinB3403
            last edited by

            @dustinb3403 said in Dumb question - linux dd write 0s to multiples disks at once:

            @travisdh1 said in Dumb question - linux dd write 0s to multiples disks at once:

            @dustinb3403 said in Dumb question - linux dd write 0s to multiples disks at once:

            @scottalanmiller said in Dumb question - linux dd write 0s to multiples disks at once:

            With a single command, no. But you can run several commands at once.

            That would suffice, what would it look like?

            tack a ; to the end of each dd command and put them all on a single line

            as

            dd if=/dev/zero of=/dev/sdb bs=4k; dd if=/dev/zero of=/dev/sdc bs=4k; dd if=/dev/zero of=/dev/sdd bs=4k; dd if=/dev/zero of=/dev/sde bs=4k

            right?

            yes

            1 Reply Last reply Reply Quote 0
            • DustinB3403D
              DustinB3403
              last edited by

              It works!

              Now just to go home and drink and come back to this Monday.

              Thanks guys!

              1 Reply Last reply Reply Quote 1
              • scottalanmillerS
                scottalanmiller @DustinB3403
                last edited by

                @dustinb3403 said in Dumb question - linux dd write 0s to multiples disks at once:

                @travisdh1 said in Dumb question - linux dd write 0s to multiples disks at once:

                @dustinb3403 said in Dumb question - linux dd write 0s to multiples disks at once:

                @scottalanmiller said in Dumb question - linux dd write 0s to multiples disks at once:

                With a single command, no. But you can run several commands at once.

                That would suffice, what would it look like?

                tack a ; to the end of each dd command and put them all on a single line

                as

                dd if=/dev/zero of=/dev/sdb bs=4k; dd if=/dev/zero of=/dev/sdc bs=4k; dd if=/dev/zero of=/dev/sdd bs=4k; dd if=/dev/zero of=/dev/sde bs=4k

                right?

                That makes one run right after the other, they don't run at the same time.

                1 Reply Last reply Reply Quote 2
                • scottalanmillerS
                  scottalanmiller
                  last edited by

                  @travisdh1 said in Dumb question - linux dd write 0s to multiples disks at once:

                  dd if=/dev/zero of=/dev/sdb bs=4k

                  nohup dd if=/dev/zero of=/dev/sdb bs=4k &
                  nohup dd if=/dev/zero of=/dev/sdc bs=4k &
                  nohup dd if=/dev/zero of=/dev/sdd bs=4k &
                  

                  Like that 🙂

                  DustinB3403D travisdh1T stacksofplatesS 3 Replies Last reply Reply Quote 2
                  • DustinB3403D
                    DustinB3403 @scottalanmiller
                    last edited by

                    @scottalanmiller but nohup from the live us isn't an option.

                    scottalanmillerS black3dynamiteB 2 Replies Last reply Reply Quote 0
                    • scottalanmillerS
                      scottalanmiller @DustinB3403
                      last edited by

                      @dustinb3403 said in Dumb question - linux dd write 0s to multiples disks at once:

                      @scottalanmiller but nohup from the live us isn't an option.

                      Oh, what shell are you in?

                      1 Reply Last reply Reply Quote 0
                      • black3dynamiteB
                        black3dynamite @DustinB3403
                        last edited by

                        @dustinb3403 said in Dumb question - linux dd write 0s to multiples disks at once:

                        @scottalanmiller but nohup from the live us isn't an option.

                        Using Ubuntu live usb?

                        1 Reply Last reply Reply Quote 0
                        • DustinB3403D
                          DustinB3403
                          last edited by

                          Centos 7

                          1 Reply Last reply Reply Quote 0
                          • scottalanmillerS
                            scottalanmiller
                            last edited by

                            What is the result of this command..

                            echo $0
                            
                            DustinB3403D 1 Reply Last reply Reply Quote 0
                            • DustinB3403D
                              DustinB3403 @scottalanmiller
                              last edited by

                              @scottalanmiller said in Dumb question - linux dd write 0s to multiples disks at once:

                              What is the result of this command..

                              echo $0
                              

                              Not at the office, so I don't know

                              1 Reply Last reply Reply Quote 0
                              • black3dynamiteB
                                black3dynamite
                                last edited by

                                https://unix.stackexchange.com/revisions/284489/1

                                dd if=/dev/zero | tee >(dd of=/dev/sdb) >(dd of=/dev/sdc) | dd of=/dev/sdd
                                
                                1 Reply Last reply Reply Quote 0
                                • ObsolesceO
                                  Obsolesce @DustinB3403
                                  last edited by

                                  @dustinb3403 said in Dumb question - linux dd write 0s to multiples disks at once:

                                  Is it possible to use linux DD to write 0's to multiple disks at once?

                                  The goal would be to wipe 4 drives at once.

                                  What if you create a SW RAID 10 with them quick, then write zeros?

                                  scottalanmillerS 1 Reply Last reply Reply Quote 1
                                  • A
                                    Alex Sage
                                    last edited by

                                    Does writing zeros to an SSD drive affect the drive life?

                                    scottalanmillerS 1 Reply Last reply Reply Quote 0
                                    • 1
                                      1337
                                      last edited by 1337

                                      No need to wipe all the disks. It's a waste of time.

                                      • If you wanted to erase the partition table you don't have to erase the whole disk. Just the first / last bytes of the drive. Or just remove it with fdisk or parted.
                                      • If you wanted to remove superblocks after an earlier md raid installation you wouldn't need to wipe the disk either. You do: mdadm --zero-superblock /dev/sdX

                                      You could also use wipefs -a /dev/sdX to remove just partition tables and raid signatures - if you have it installed.

                                      And as soon as you put together a raid-10 it will start synchronizing the disk and write the same zeros one more time.

                                      If you really, really wanted to wipe the drive so no residual data where on them, wipe just what is needed to make a raid-10 array out of it. Then wipe the array with zeros, as a block device. It will save a lot of time. As the synchronization process will write the zeros for you on the other drives.

                                      1 Reply Last reply Reply Quote 3
                                      • scottalanmillerS
                                        scottalanmiller @Obsolesce
                                        last edited by

                                        @obsolesce said in Dumb question - linux dd write 0s to multiples disks at once:

                                        @dustinb3403 said in Dumb question - linux dd write 0s to multiples disks at once:

                                        Is it possible to use linux DD to write 0's to multiple disks at once?

                                        The goal would be to wipe 4 drives at once.

                                        What if you create a SW RAID 10 with them quick, then write zeros?

                                        That would be faster. Or RAID 1. Any RAID, actually.

                                        1 Reply Last reply Reply Quote 0
                                        • scottalanmillerS
                                          scottalanmiller @Alex Sage
                                          last edited by

                                          @aaronstuder said in Dumb question - linux dd write 0s to multiples disks at once:

                                          Does writing zeros to an SSD drive affect the drive life?

                                          No, shouldn't affect anything unless you are trying to obfuscate the old data

                                          1 Reply Last reply Reply Quote 0
                                          • M
                                            manxam
                                            last edited by manxam

                                            "screen" is available within the bootable USB.
                                            screen dd if=/dev/zero of=/dev/sda1 bs=1M
                                            Ctrl-A then D to detach
                                            Up arrow then enter 3 more times...

                                            This will continue to run even if the console is lost (ssh) or if the user logs out
                                            screen -R to re-attach a session if you want to check the status

                                            Having said that:
                                            dd if=/dev/zero of=/dev/sda bs=512 count=1 conv=notrunc
                                            Should take only seconds and delete the partition table and is less work than using fdisk in the event that wipefs isn't available on the bootable USB.

                                            1 Reply Last reply Reply Quote 2
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