Art Eschenlauer's Blog
From http://linux.die.net/man/1/colordiff
colordiff is a wrapper for diff and produces the same output as diff but with coloured syntax highlighting at the command line to improve readability.
The output is similar to how a diff-generated patch might appear in Vim or Emacs with the appropriate syntax highlighting options enabled.
The colour schemes can be read from a central configuration file or from a local user ~/.colordiffrc file.
To enjoy on Ubuntu:
sudo apt install colordiff
In addition to checking that /etc/ssh/sshd_config is correct, you will want to check that the permissions on the user’s home directory and ~/.ssh are correct. I have gathered that:
[foo@foo-nas ~/.ssh]$ ls -la -D "" total 14 drwx------ 2 foo foogrp 3 . drwxr-x--- 5 foo foogrp 15 .. -rw-r--r-- 1 foo foogrp 395 authorized_keys
ZFS is best used in a RAID configuration:
A laptop does not typically offer the advantage of being able to house so many disks. Nevertheless, ZFS offers other advantages that make it sensible to use on a laptop:
I have two drives in my laptop:
It might make sense at some point to replace the expansion drive with a higher capacity drive. For now, I installed ZFS onto the expansion drive, inspired by:
http://www.ibm.com/developerworks/library/l-zfs/index.html
Ideally, I would have a mirror between my OS drive and a partition on the expansion drive; however, not only is my expansion drive fairly limited, but also this is my first attempt at using ZFS beyond FreeNAS, which handles ZFS at arm’s length. So, I decided to start with something simple: ZFS on an unmirrored disk.
Although the kernel in Ubuntu 16.04 LTS supports ZFS, I needed to install the ZFS utils:
apt-get install zfsutils-linux
to use the zpool and zfs commands.
If I am reading the man page correctly for the zpool command (which says that the device name path is relative to /dev), I could have deduced the invariant id for my disk
ata-HGST_HTS725050A7E630_RCF50ACE1P7B7M
using the command:
ls -l /dev/disk/by-id
and then creating and mounting the “zpool” called “zpdrone” using the command
zpool create zpdrone disk/by-id/\
ata-HGST_HTS725050A7E630_RCF50ACE1P7B7MUnfortunately for me, I hadn’t quite understood the man page, so I went with the first thing that worked:
zpool create zpdrone sda
I next created a ZFS file system (“drone”) and enabled compression:
zfs create zpdrone/drone
zfs set compression=on zpdrone/drone
I proceeded to add some files to my file system (which was mounted at /zpdrone/drone), rebooted, and verified that I could see the files.
Shortly thereafter, I booted with an external drive attached.
I found that the external drive was assigned to sda, so my expansion drive was assigned to sdb, and consequently my zpool didn’t get mounted; this gave me the opportunity to learn how to untangle the mess that I had caused. As it turns out, this was not hard to do.
The first step was to “export” the pool (roughly equivalent to sync’ing and unmounting it):
zpool export zpdrone
The second step was to “import” the pool using the disk ID and pool ID. I obtained the pool ID (269414010796639802) from the output of
zpool import
and then told zpool to import it by searching under
/dev/disk/byid
for a zpool with the zpool ID
zpool import -d /dev/disk/by-id \
269414010796639802Once again, my file system was mounted at
/zpdrone/drone.
Subsequently, I could boot with an attached external hard drive, and, as expected,
zpool status
showed the disk ID for the pool
(ata-HGST_HTS725050A7E630_RCF50ACE1P7B7M).