Mark's Blog

Enttäuscht wird man von Netcup, wenn man von Vservern von Rackspace oder Amazon ausgeht. Netcup setzt sein Angebot anders um und es sind viele wichtige Dinge technisch nicht möglich, was zu Frust führt und von denen ich einige nachfolgend beschreibe. Als studierter Informatiker erscheint mir “Linux-Vserver” vielmehr eher einer Chroot Umgebung mit Extras wie Prozess-Separation oder “logischen Serverpartitionen“ zu entsprechen. An sich Techniken, die mangels Overhead performant sind und an denen es nichts auszusetzen gibt. Wenn man denn soetwas wollte. Kunden, deren Erwartungen durch Rackspace, Amazon oder Strato virtuelle Server (“Vserver”) geprägt wurden, wie ich, fühlen sich durchaus in die Irre geführt¹:

Der Unterschied zeigt sich, Read more »

Recently I’ve rented a server partition from a German provider which turned out to be a linux-vserver partition. About five or six years ago I have experimented with linux-vserver myself, still have headaches when it comes to its security implications…

Unfortunately the provider has not offered any Gentoo images. Despite that and by the means of the rescue shell, I have installed Gentoo on it. Here is how: Read more »

Tags: Gentoo, know-how, linux-vserver

For a project of mine I have been looking today on key/value stores. Redis, Tokyo Cabinet and Memcache are the popular ones, but I have been interested in benchmarking the distributed species of its kind (“DKVS”). Those are needed in high scalable systems as replacement for traditional databases, which happen not to scale well.

These are the criteria which the DKVS must meet:

1. distribute data amongst one to four nodes (and the more the better)
2. nodes must be able to be added on-the-fly,
3. … and removed on-the-fly
4. data has to be held redundantly, even after removal of a node
5. data access has to be transparent, i.e. every node shall be equal
6. scale with additional nodes – for every additional node there should be an increase of GET and SET operations per second up to the maximum dictated by the hardware and network

Read more »

Tags: distributed system, key/value store, nosql, systems architecture

Amazon and Rackspace both provide virtualized servers billed per hour. That makes deploying scalable applications, especially with distributed key/value stores, very handy: You could launch new servers just as load, customer count or requests increase.

Today I’ve run the Redis benchmark on the SheevaPlug, Amazon EC2 and Rackspace Cloudservers to see where a small Redis database will perform the best. Read more »

Tags: Amazon EC2, benchmark, cloud, Rackspace CloudServers, Redis, SheevaPlug