Disk Encryption With LUKS

Originally meant for Linux, the Linux Unified Key Setup (LUKS) is “a disk encryption specification created by Clemens Fruhwirth in 2004”.1 LUKS is what I used to encrypt a partition of my external hard drive. As an experiment, I did the following:

  • Create a disk partition or partitions using fdisk. In my case, I created one partition that became /dev/sdc1 on my host computer.
  • Encrypt the partition using cryptsetup:
    • cryptsetup -vv luksFormat /dev/sdc1 where -v is for verbosity
  • You will be prompted for a password that will be used to lock the disk partition.
  • Unlock the partition:
    • cryptsetup -vv open /dev/sdc1 whatever_name
  • Format the partition to whatever filesystem you want (e.g. ext4):
    • mke2fs -vv -t ext4 /dev/mapper/whatever_name
  • Mount the partition and test it:
    • mount -t ext4 /dev/mapper/whatever_name /mnt/t01

To remove the external drive, you must first unmount the decrypted partition:

    umount /mnt/t01

Then, wipe the existing mapping and wipe the encryption key from kernel memory:

    cryptsetup close /dev/mapper/whatever_name

All the above commands were done as root. The host was running Ubuntu 20.04.1 LTS and the external hard drive was connected via USB 3.

I will continue with my experiments with encrypted disks. I am particularly interested in how to auto mount the encrypted disk at boot time. Luckily, there are a number of web articles on this matter. In a future article, I will try some of the procedures used in those web articles and discuss my own experience with auto mounting.

1 https://en.wikipedia.org/wiki/Linux_Unified_Key_Setup

The TOP 500 Supercomputers (June 2019) – 100% Linux

The top 500 supercomputers of Planet Earth all use Linux. This has been the case for some time now. Naturally, performance share for Linux is 100%. Indeed, it is great to see Linux dominate the high performance computing platform.

CentOS and the Cray Linux Environment seem to be the popular choices for operating systems. Not surprisingly, Red Hat Enterprise Linux is also represented.

Processors from Intel are commonly used and IBM’s Power9 processors are used as well though not as common. Note, however, that the top 2 supercomputers, Summit and Sierra, use Power9 processors running Red Hat Enterprise Linux.

GPUs are also installed in some of the supercomputers as coprocessors. Nvidia cards are usually the choice for the GPU coprocessors, probably due to the vast amount of software supporting Nvidia GPUs for computational tasks. The Summit and Sierra supercomputers use the Nvidia Volta GV100 as coprocessors.

You can generate list statistics for the top 500 supercomputers at this link: https://www.top500.org/statistics/list/