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{ Category Archives } Linux

Linux news and information.

Haveged - A True Random Number Generator

I admit that my last post sucked. I've been working on a few things that I want to blog about, but it's going to take time to get all my ducks in a row. So, that post was mostly "filler". Read as "I haven't blogged in a while, and should probably put something up". Sorry. […]

Encrypted ZFS Filesystems On Linux

This is just a quick post about getting a fully kernel-space encrypted ZFS filesystem setup with GNU/Linux, while still keeping all the benefits of what ZFS offers. Rather than using dmcrypt and LUKS, which would bypass a lot of the features ZFS brings to the table, encryptfs is our ticket. The reason this is so […]

Appropriate Use Of "kill -9 "

There are times when "kill -9" is the only time you can kill a PID that is behaving badly. However, it's usually not needed if you know your signals. When I encounter a badly behaving program, here is the procedure I usually take. First, I'll send a SIGTERM (kill -15) to the PID. Sometimes this […]

Network Gotcha

So, we were just recently troubleshooting a connectivity issue at the office. Some things seemed slow, other things seemed fast. It was hard putting a finger on it. So, we starting pinging random stuff, trying to figure out exactly what was going on. Is it routing? Is in DNS? Is it layer 2? What gives? […]

Libvirt, Tyan Motherboards, and UUID

I recently built two servers that I plan on using for a sandbox with various technologies (Infiniband, ZFS, RDMA, GlusterFS, Btrfs, Ceph, LXC, KVM, etc, etc, etc). So, getting everything installed and running, I ran into a rather interesting bug. I installed KVM and libvirt, and started rolling out some virtual machines. I wanted to […]

Aptitude Madness

I always use the "-R" or "--without-recommends", and this is why: root@yin:~# aptitude install virtinst The following NEW packages will be installed: acl{a} colord{a} consolekit{a} dconf-gsettings-backend{a} dconf-service{a} fontconfig{a} fontconfig-config{a} hicolor-icon-theme{a} libatk1.0-0{a} libatk1.0-data{a} libcairo-gobject2{a} libcairo2{a} libck-connector0{a} libcolord1{a} libcups2{a} libdatrie1{a} libdbus-glib-1-2{a} libdconf0{a} libdrm-intel1{a} libdrm-nouveau1a{a} libdrm-radeon1{a} libdrm2{a} libexif12{a} libfdt1{a} libfile-copy-recursive-perl{a} libfontconfig1{a} libgd2-xpm{a} libgdk-pixbuf2.0-0{a} libgdk-pixbuf2.0-common{a} libgl1-mesa-dri{a} libgl1-mesa-glx{a} libglapi-mesa{a} libgphoto2-2{a} […]

Zombie Proccess- What They Are and How To Handle Them

First off, a zombie process isn't really a process. At least it's not executing anymore. A zombie process is more of a "state", and that state is "defunct". However, we typically refer to them as "zombie processes", so I'll stick with convention here. Second, a zombie process on a Unix system is a child process […]

Install ZFS on Debian GNU/Linux

UPDATE (May 06, 2012): I apologize for mentioning it supports encryption. Pool version 28 is the latest source that the Free Software community has. Encryption was not added until pool version 30. So, encryption is not supported natively with the ZFS on Linux project. However, you can use LUKS containers underneath, or you can use […]

Mount Raw Images

Just recently, I needed to mount a KVM raw image file, because it was depending on a network mount that was no longer accessible, and any attempts to interact with the boot process failed. So, rather than booting off a live CD, or some other medium, I decided to mount the raw image file. After […]

A Note About Removing Files With find(1)

I've seen on the internet, and elsewhere, that when there are too many arguments for rm(1) to handle, that the following command will suffice: % find /path -exec rm -rf {} \; While certainly functional, it's not optimal. If there are thousands of files (as is often the case at my job), this command is […]

Use Your SSH Client To Help Prevent Stupid Mistakes

I have chosen the path of system administration for my career. It's been very rewarding, and I really love my job. However, there are times when I make stupid mistakes that cost others money. I'm sure we've all been there. It's stressful, embarrassing and can really shake you up, if you mistake is bad enough. […]

My Tmux Hardstatus Theme

Recently, I've made the switch from GNU Screen to Tmux for my remote terminal multiplexor. I still prefer GNU Screen for serial connections, however (something the Tmux developers don't seem to think is important). So, when getting it setup, I wanted my hardstatus line to imitate my GNU Screen hardstatus line as closely as possible. […]

I Am Going To OLF

I will be attending the Ohio Linux Fest this September (in about two weeks) giving a talk on "Password Theory and Breaking Encrypted Filesystems". The talk covers some theory on what exactly makes a "secure password", including some mathematics, entropy, random number generators, shadowed passwords, salts, rainbow tables and cryptographic hashes. I end the talk […]

OpenSSH Best Practices

This post comes from Matt Taggart, who put together a document about the best practices for using OpenSSH. A lot of the points brought up in that document rang the bells of common sense, and are so good, it's worth blogging about in hopes that the points mentioned therein reach as many as possible. I've […]

Why Unix Is Superior

Quick post, outlining what I think makes the Unix family of operating systems superior, including "unix-like" operating systems such as GNU/Linux, BSD, and others. Of course, the list isn't exhaustive- it's just something I threw together in 10 minutes. The motivation of the post was a discussion in ##unix on Freenode. The command line interface. […]