Life the universe and everything

Archive for the ‘How to’ Category

Vauxhall Signum Low Power and Slow

with 2 comments

Vauxhall engine

I have recently solved a problem with my Vauxhall Signum 2004 1.9i Diesel and wanted to share.

The symptoms were:

  • Lacking power, slow to accelerate
  • EML comes on at engine start but goes off after driving a short distance
  • Noisy engine during acceleration
  • If over revved the Signum goes into ‘limp mode’ and the engine management light comes on until the engine is restarted

I found an excellent post titled Poor Performance … Check your boost pipes. Boost pipes are sometimes called vacuum pipes. I bought some 4mm internal diameter silicon pipe from ebay and started checking the pipes in the engine.

Within 10 minutes I found that one of the very short sections of rubber (just above the radiator close to the battery) had a split in it. I removed this and replaced it with a short section of my new pipe. I was doubtful that that was the cause of all my problems though.

I decided to go for a test drive …… what a difference. It was driving like a new car, turbo kicking in, powering away, a pleasure to drive. I have been embarrassed when pulling into traffic as it was taking up to 30 seconds to reach 30 mph before this fix.

On the same forum was another similar post with plenty of pictures called 2.2dti silicon boost pipes fitted (photos included). Thank you guys for posting your solutions which gave me the confidence to do it myself.


Written by barnabyfry

April 11, 2012 at 8:44 pm

Posted in How to, Personal

Poor mans failover

with 18 comments

This ‘How-to’ blog is primarily intended for webmasters with database driven websites (but also covers effective but cheap IP failover for all webmasters) who need to achieve high availability without high expense and is based on my own experience.

So why am I writing this? Well … at the time of writing I am struggling to find any resources for cheap, high availability and fail-over techniques which cover the failover scenarios a web master might face. The articles I’ve found also tend to be highly technical. I hope I can offer you a method which offers effective failover and allows you to maintain high availability using simple, effective and cheap resources.

A word of warning! We all know that 5 nines of availability is the goal (99.999% uptime) but that kind of availability does not come cheap. This article is intended for website owners who can live with a few minutes of downtime now and again but would like to avoid a few hours.

Here is the summary of main points/requirements:

  1. You must control your own DNS
  2. You need multiple websites and/or multiple databases
  3. You pay for a DNS failover service

DNS nameservers

You must have control of your DNS nameservers in order to specify a DNS failover service. I have shared hosting which comes with its own name servers but I use a managed DNS service at ZoneEdit for my primary name server and list my hosts DNS as secondary name server. Experience has taught me never to keep all my eggs in one basket. I use Zone Edit because they offer the failover service.

[update]I have since swapped to as they offer a 2-4 minute failure detection/recovery time[/update]

Multiple Websites

Here’s my scenario. I have shared hosting for my database driven (MySQL) website and I have a server in my office which has the same files. I use this server for development and testing and it makes sense to use it as my failover server for when my main website fails. I also have an installation of MySQL on this server. The office has broadband with a fixed IP address.

OK, so not everyone has the luxury of a development server … but you do have the option of very cheap hosting at a different hosting company!!! If you need high availability you need somewhere else to take over when your primary site goes down. You simply need to ensure that the failover website has a reasonably up to date version of the live site.


I backup my live MySQL database every day and I ‘restore’ the latest backup to my office server as often as I remember.

I learned to my cost that database downtime accounts for the majority of my sites total down-time. Here’s where having a secondary database gives you another added advantage. With most database connections you can write script (php, asp etc) which checks the availability of a database and if it fails you instantly and seamlessly connect to your backup database and the page still executes on the primary website. I use such a script as a global connection which is used on every page. The classic ASP version is:

Set objConn=Server.CreateObject (“ADODB.Connection”) connstring, “”, “”
If objConn.errors.count>0 Then
objConn.close connstring2, “”, “”
End If

If my live database goes down (which it does) my users are unaffected because my scripts instantly switch to the secondary database.

Failover Service

For at most around $11 per year (multi-credit purchase is much cheaper) the ZoneEdit failover service will retrieve a specified page from your website every 10-15 minutes. It uses simple regular expressions to check for valid html content. If it cannot retrieve the page it dynamically changes the DNS pointers for your website to the IP address which you specify in the failover service. In my case the office IP address but could simply be a second hosting company IP address.

What happens then?

New visitors to the site will mostly be directed to the backup site. Visitors who were on-line at the time will lose the connection. This is because their browser will continue to attempt to access the ip address it has cached for the domain. This is another slight compromise.


Given a secondary website and/or database on a different server we can use simple scripting to connect seamlessly to a secondary database should the primary fail. Using a DNS IP failover service can provide high availability (10 mins average detection time at failover) by redirecting users to a specified secondary ip address.

This is my guerilla method for cheap fail-over and it has proved very reliable. I hope it is of use.

Written by barnabyfry

March 22, 2007 at 5:24 pm

Posted in How to