wipe all drives on system

chonk0 · 02-16-2018, 12:16 PM

Hello Id like to wipe all my drives on a machine at once with dd. Would dd if=/dev/zero of=/dev/* bs=16M work?

keefaz · 02-16-2018, 12:19 PM

No, look in /dev directory: ls /dev/*
You don't want to fill all these device files

What sort of drives is? And you run the command from live system? (OS mounted from removeable media?)

chonk0 · 02-16-2018, 12:30 PM

https://i.imgur.com/YGhMJMT.png

Its a live system yes. Im logged in remotely via terminal.

I dont have KVM so I wanna make sure i wipe everything at once. Standard SATA disks.

chonk0 · 02-16-2018, 12:35 PM

Quote:

Originally Posted by keefaz

No, look in /dev directory: ls /dev/*
You don't want to fill all these device files

What sort of drives is? And you run the command from live system? (OS mounted from removeable media?)

https://i.imgur.com/YGhMJMT.png

Its a live system yes. Im logged in remotely via terminal.

I dont have KVM so I wanna make sure i wipe everything at once. Standard SATA disks.

keefaz · 02-16-2018, 03:37 PM

So of value for dd would be only /dev/sdb and /dev/sdc

As it is only 2 command iterations, no need to use clever loops or globing
Just run the command twice (1st with of=/dev/sdb, 2nd with of=/dev/sdc)
After that, there will be nothing left in these devices

chonk0 · 02-16-2018, 04:24 PM

Quote:

Originally Posted by keefaz

So of value for dd would be only /dev/sdb and /dev/sdc

As it is only 2 command iterations, no need to use clever loops or globing
Just run the command twice (1st with of=/dev/sdb, 2nd with of=/dev/sdc)
After that, there will be nothing left in these devices

Thanks

keefaz · 02-16-2018, 05:36 PM

Note that depending on drive size, it may take a while to finish

With fdisk and mdadm tools, it's a matter of less than one minute to delete partitions and start over

Code:

mdadm --zero-superblock /dev/sdb
mdadm --zero-superblock /dev/sdc
fdisk /dev/sdb (delete partitions, write changes)
fdisk /dev/sdc (delete partitions, write changes)

AwesomeMachine · 02-16-2018, 07:58 PM

Dd will run multiple instances. But I've never been able to get globbing to work with it.

fatmac · 02-17-2018, 09:17 AM

To overwrite data partitions, you could use shred.

To remove file allocation tables, use dd & /dev/zero to overwrite the first MB (or two) of your disks, sdb & sdc, (bs=1M count=2)

Using dd to erase your two disks will take a considerable time.

Stev8 · 02-17-2018, 05:53 PM

you can also use
sudo cfdisk

or gparted on the live cd.

sundialsvcs · 02-18-2018, 08:26 AM

These days, the fastest way to "wipe a drive" is to use equipment with on-board encryption, and simply load a new random key-value into the drive firmware. This will render the entire contents pragmatically unrecoverable. (To anyone but sophisticated law-enforcement, and "so far as we know.") Anyhow, it will quickly zap the drive, and do it in a way that's satisfactory to your liability-insurance carrier. With today's ultra-high capacity drives, other alternatives take hours or days. This strategy takes five seconds.