Nikolaus Rath's Website

ZFS-on-NBD - My Verdict

I've been evaluating a ZFS-on-NBD based backup system for several weeks. I've now made a decision if I want to adopt this new setup, or stick with S3QL.

To make it short, I will drop my experiments with ZFS and continue using S3QL.

The main reasons for this are that the advantages of using ZFS are not as big as I had hoped, and that I discovered additional problems with the setup. But let me start with the positive things …

S3QL vs ZFS-on-NBD

When I created S3QL in 2008, the Cloud Storage and Linux filesystem landscape looked rather different than today: there was no filesystem that supported compression, encryption, or de-duplication of data. The only relevant cloud storage system was Amazon S3, and it only offered eventual consistency.

S3QL was designed to fill these gaps: I wanted to be able to store compressed, encrypted, and de-duplicated backups in the cloud, without being tied to a particular backup software. It think it has served …

MATLAB is a terrible programming language

I consider it fairly uncontroversial that, as a programming language, MATLAB is a terrible choice. However, I found out that to some people this isn't actually obvious at all - especially when their first exposure to programming was through MATLAB. Explaining why the MATLAB language is so bad isn't easy to do in a quick hallway conversation, so I wrote this blog post as a resource I can refer people to.

This post is inspired by Eevee's excellent PHP: A fractal …

My experience

I recently found myself in the situation of wanting to get out of a lease before its contractual maturity date. The most cost-effective way to do so is to transfer the lease to someone else. is one of the companies that promises to bring together people for such transactions.

I will say straightaway that I was very skeptical. Swapalease charges not just a provision when the lease is actually transferred, but you also have to pay to list …

BTRFS Reliability - a datapoint

A little while ago I blogged about SSD caching under Linux and promised to report back should I encounter any problems with the (rather complex) stack of btrfs on dm-crypt on lvm on bcache. I have now run this setup for several months and indeed encountered a few issues.

The first issue is that attempting to read from a freshly created file sometimes results in I/O errors that persist until the system is rebooted. With hindsight, I expect that …