{ inercia }

PacketFence: a network access control solution

Fri, 10 May 2013 23:55:01 +0200

PacketFence: a network access control solution:

PacketFence is a fully supported, trusted, Free and Open Source network access control (NAC) solution. Boasting an impressive feature set including a captive-portal for registration and remediation, centralized wired and wireless management, 802.1X support, layer-2 isolation of problematic devices, integration with the Snort IDS and the Nessus vulnerability scanner; PacketFence can be used to effectively secure networks - from small to very large heterogeneous networks.

How do you estimate on an Agile project?

Thu, 09 May 2013 00:25:18 +0200

How do you estimate on an Agile project?:

Estimation can be a diﬃcult beast to deal with; more so on an Agile project. How do you estimate when you don’t have a list of requirements that is complete or signed-oﬀ by the customer? Or a nailed-down schedule? What should your currency of estimation be? How do you estimate on a distributed team? Is it worth estimating at all?

Dependency Inversion in practice

Wed, 01 May 2013 22:55:47 +0200

Dependency Inversion in practice

Copperhead

Fri, 26 Apr 2013 08:44:03 +0200

Copperhead:

Data parallelism brought to Python from Nvidia Research.

Strategy: Using Lots of RAM Often Cheaper than Using a Hadoop Cluster

Wed, 24 Apr 2013 23:01:58 +0200

Strategy: Using Lots of RAM Often Cheaper than Using a Hadoop Cluster:

For smaller problems memory has reached a GB/$ ratio where it is technically and financially feasible to use a single server with 100s of GB of DRAM rather than a cluster. Given the majority of analytics jobs do not process huge data sets, a cluster doesn’t need to be your first option. Scaling up RAM saves on programmer time, reduces programmer effort, improved accuracy, and reduces hardware costs.

objgraph: hunting memory leaks

Mon, 01 Apr 2013 20:15:04 +0200

objgraph: hunting memory leaks

How we use Python at Spotify

Thu, 21 Mar 2013 10:38:22 +0100

How we use Python at Spotify

Redis persistence

Wed, 20 Mar 2013 13:47:00 +0100

Redis persistence:

I had the idea Redis did not implement “reliable” persistence. I’ve always used it as a in-memory key-value storage, mostly from Python. So I was looking for some persistence solutions when I found this explanation by one of the developers where he tries to demystify Redis persistence.

He goes on the common aspects to consider when persisting databases, explaining the interactions with the OS and why you can’t assure all data is saved to disk unless you want to do all your I/O operations synchronous (and that is something rather expensive). Then he explains the main persistence alternatives: snapshottings and AOF files.

Snapshots just dump the whole dataset to a disk image, but they are expensive operations and cannot be performed too often (they are usually done every 5 minutes or so). In contrast, AOF files do little I/O by saving to a file all the operations as they happen, right in the same order as they are executed by the server, so they can be replayed in case of a crash. In my view, and depending on the fsync policy you use (that forces a commit of data to disk), AOF files can provide the same reliability as any other conventional database (ie, PostgreSQL). And, as the author explains, both methods can be combined for increased security:

From a more practical point of view Redis provides both AOF and RDB snapshots, that can be enabled simultaneously (this is the advised setup, when in doubt), offering at the same time easy of operations and data durability.

Async I/O for Python 3

Tue, 19 Mar 2013 17:34:58 +0100

Async I/O for Python 3:

A presentation by Guido van Rossum on how Tulip is going to replace gevent, Tornado and all those incompatible libraries…

Using Redis as LINE storage

Tue, 19 Mar 2013 00:06:00 +0100

Using Redis as LINE storage:

How they used Redis as storage in LINE, and how they scaled up with the help of Hadoop, HBase and some other tools…

Nginx & WebSockets

Fri, 15 Mar 2013 00:32:27 +0100

Nginx & WebSockets:

There is WebSockets support in Nginx since versión 1.3.13. See how to use it here

Plop: Python Profiler With Call Graphs

Wed, 13 Mar 2013 13:33:53 +0100

Plop: Python Profiler With Call Graphs:

A new profiler for Python…

Under the Hood: Building out the infrastructure for Graph Search

Thu, 07 Mar 2013 12:12:34 +0100

Under the Hood: Building out the infrastructure for Graph Search

Why Intel can't seem to retire the x86

Wed, 06 Mar 2013 17:09:51 +0100

Why Intel can't seem to retire the x86:

The x86 microarchitecture is another aged technology, and it has survived more assassination attempts than Fidel Castro. What makes the number of attempts on x86 more interesting is that Intel is the one who keeps trying to take it out.

The BitTorrent Engineering blog

Tue, 05 Mar 2013 11:03:39 +0100

The BitTorrent Engineering blog:

They have recently opened the blog so there is not much content yet, but I’ve found two interesting articles:

Thialﬁ: A Client Notiﬁcation Service for Internet-Scale Applications

Thu, 28 Feb 2013 10:43:39 +0100

Thialﬁ: A Client Notiﬁcation Service for Internet-Scale Applications:

A paper on Thialfi, the framework used at Google for notifications. They claim they can scale to millions of users, and with a delay of less than a second…

The purpose of estimations

Wed, 27 Feb 2013 19:15:34 +0100

The purpose of estimations

Python Profiling tools

Tue, 26 Feb 2013 12:23:12 +0100

Python Profiling tools

Vitess

Sun, 24 Feb 2013 12:51:29 +0100

Vitess:

A scalable RPC interface to MySQL, with client-side sharding, limited ACID support and more

Pypy vs Gevent vs Node.Js

Wed, 20 Feb 2013 00:38:39 +0100

Pypy vs Gevent vs Node.Js:

A new comparison on the performance of Python and Node.JS. As we could expect, Node outperforms Python in terms of latency, specially for short connections, but, for big data transfers, there is a negligible difference between both languages…