Category: Linux

WordPress Multisite on Debian

WordPress (a common CMS for blogs) is designed to be copied to a directory that Apache can serve and run by a user with no particular privileges while managing installation of it’s own updates and plugins. Debian is designed around the idea of the package management system controlling everything on behalf of a sysadmin. When […]

Linux

QEMU for ARM Processes

I’m currently doing some embedded work on ARM systems. Having a virtual ARM environment is of course helpful. For the i586 class embedded systems that I run it’s very easy to setup a virtual environment, I just have a chroot run from systemd-nspawn with the --personality=x86 option. I run it on my laptop for my […]

Linux

More KVM Modules Configuration

Last year I blogged about blacklisting a video driver so that KVM virtual machines didn’t go into graphics mode [1]. Now I’ve been working on some other things to make virtual machines run better. I use the same initramfs for the physical hardware as for the virtual machines. So I need to remove modules that […]

Linux

Video Mode and KVM

I recently changed my KVM servers to use the kernel command-line parameter nomodeset for the virtual machine kernels so that they don’t try to go into graphics mode. I do this because I don’t have X11 or VNC enabled and I want a text console to use with the -curses option of KVM. Without the […]

Linux

Ethernet Interface Naming With Systemd

Systemd has a new way of specifying names for Ethernet interfaces as documented in systemd.link(5). The Debian package should keep working with the old 70-persistent-net.rules file, but I had a problem with this that forced me to learn about systemd.link(5). Below is a little shell script I wrote to convert a basic 70-persistent-net.rules (that only […]

Linux

BTRFS Status April 2014

Since my blog post about BTRFS in March [1] not much has changed for me. Until yesterday I was using 3.13 kernels on all my systems and dealing with the occasional kmail index file corruption problem. Yesterday my main workstation ran out of disk space and went read-only. I started a BTRFS balance which didn’t […]

Linux storage

Swap Space and SSD

In 2007 I wrote a blog post about swap space [1]. The main point of that article was to debunk the claim that Linux needs a swap space twice as large as main memory (in summary such advice is based on BSD Unix systems and has never applied to Linux and that most storage devices […]

Linux storage

Is Portslave Still Useful?

Portslave is a project that was started in the 90’s to listen to a serial port and launch a PPP or SLIP session after a user has been authenticated, I describe it as a “project” not a “program” because a large part of it’s operation is via a shared object that hooks into pppd, so […]

Linux

Hetzner now Offers SSD

Hetzner is offering new servers with SSD, good news for people who want to run ZFS (for ZIL and/or L2ARC). See the EX server configuration list for more information [1]. Unfortunately they don’t specify what brand of SSD, this is a concern for me as some of the reports about SSD haven’t been that positive, […]

Linux

ZFS on Debian/Wheezy

As storage capacities increase the probability of data corruption increases as does the amount of time required for a fsck on a traditional filesystem. Also the capacity of disks is increasing a lot faster than the contiguous IO speed which means that the RAID rebuild time is increasing, for example my first hard disk was […]

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