Category: Software

Agile Is Dead (Long Live Agility)

March 12th, 2014, 4 Comments

In an intriguing post, PragDave laments how empty the word “agile” has become. To paraphrase, I might say he’s put words to a nagging feeling I’ve had: that there are entire books about agile, conferences about agile, hallway conversations I’ve heard about whether somebody is doing this-or-that agile practice correctly. Which, when it comes down […]

Backing up every few minutes with simplesnap

February 13th, 2014, 3 Comments

I’ve written a lot lately about ZFS, and one of its very nice features is the ability to make snapshots that are lightweight, space-efficient, and don’t hurt performance (unlike, say, LVM snapshots). ZFS also has “zfs send” and “zfs receive” commands that can send the content of the snapshot, or a delta between two snapshots, […]

Migrated from Hetzner to OVH hosting

February 7th, 2014, 5 Comments

Since August 2011, my sites such as have been running on a Xen-backed virtual private server (VPS) at Hetzner Online, based in Germany. I had what they called their VQ19 package, which included 2GB RAM, 80GB HDD, 100Mb NIC and 4TB transfer. Unlike many other VPS hosts, I never had performance problems. However, I […]

VirtFS isn’t quite ready

February 7th, 2014, 9 Comments

Despite claims to the contrary [PDF], VirtFS — the 9P-based virtio KVM/QEMU layer designed to pass through a host’s filesystem to the guest — is quite slow. I have yet to get it to perform at even 1/10 the speed of the virtual block device (VBD). That’s unfortunate, because in theory it should be significantly […]

How to fix “fstrim: Operation not supported” under KVM?

February 6th, 2014, 7 Comments

Maybe someone out there will have some ideas. I have a KVM host running wheezy, with wheezy-backports versions of libvirt and qemu. I have defined a guest, properly set discard=unmap in the domain XML file for it, verified that’s being passed to the guest, but TRIM/DISCARD is just not working. Mounting the ext4 filesystem with […]

Why and how to run ZFS on Linux

January 23rd, 2014, 15 Comments

I’m writing a bit about ZFS these days, and I thought I’d write a bit about why I am using it, why it might or might not be interesting for you, and what you might do about it. ZFS Features and Background ZFS is not just a filesystem in the traditional sense, though you can […]

Debian-Live Rescue image with ZFS On Linux; Ditched btrfs

January 22nd, 2014, 9 Comments

I’m a geek. I enjoy playing with different filesystems, version control systems, and, well, for that matter, radios. I have lately started to worry about the risks of silent data corruption, and as such, looked to switch my personal systems to either ZFS or btrfs, both of which offer built-in checksumming of all data and […]

Results with btrfs and zfs

December 7th, 2013, 20 Comments

The recent news that openSUSE considers btrfs safe for users prompted me to consider using it. And indeed I did. I was already familiar with zfs, so considered this a good opportunity to experiment with btrfs. btrfs makes an intriguing filesystem for all sorts of workloads. The benefits of btrfs and zfs are well-documented elsewhere. […]

Why are we still backing up to hardlink farms?

October 12th, 2013, 8 Comments

A person can find all sorts of implementations of backups using hardlink trees to save space for incrementals. Some of them are fairly rudimentary, using rsync –link-dest. Others, like BackupPC, are more sophisticated, doing file-level dedup to a storage pool indexed by a hash. While these are fairly space-efficient, they are really inefficient in other […]

Voice Keying with bash, sox, and aplay

August 24th, 2012, No Comments

There are plenty of times where it is nice to have Linux transmit things out a radio. One obvious example is the digital communication modes, where software acts as a sort of modem. A prominent example of this in Debian is fldigi. Sometimes, it is nice to transmit voice instead of a digital signal. This […]

Feed / Software