Archive for posts tagged ‘admin’
Back online
Kevin Day, December 27th, 2008Had some extended downtime due to server troubles that I didn’t have time to fix. Now I’m running this blog on a Slicehost slice instead of my previous “self-hosted” setup. Should be much more reliable and headache-free from now on.
Thank God! Amazon persistent storage is here
Kevin Day, August 21st, 2008I just stayed up late last night working on backup scripts for my EC2 instances, so it was great to wake up this morning to see Amazon’s latest update. With Amazon’s Elastic Block Store (EBS), ECS users can now mount persistent volumes directly to the file system. That should translate into more sleep for me.
I don’t know how many I/O requests I make in a month though, and that seems to be how they’re charging for this service. I’ll have to test it out first before I do anything serious with it.
Boot dammit!
Kevin Day, December 9th, 2007The power went out earlier today, and when it came back on I was surprised to find that my server didn’t come back online with the power. There’s no monitor attached to it, so I checked the router and everything else first before I hauled the 20th-century cathode ray tube monitor out of the closet.
It turns out that I just left the install disk in the CD drive when I was installing a package some time ago and Ubuntu was booting from the CD instead of the hard drive. D’oh! Time to change the BIOS settings so that it doesn’t happen again.
Debian’s Apache Tricks
Kevin Day, November 1st, 2007I’ve been moving this blog and other sites onto one Ubuntu box using Apache virtual hosts.
One problem I had was getting multiple sites to work properly with Debian’s setup of having a separate config file for each site. It wasn’t until I found this blog post about installing WordPress on Ubuntu that I found that you need to create a file named virtual.conf with one line: NameVirtualHost *.
If you’re running into the same problem, check out his blog post and also the Debian Administration article on virtual hosts.
Also, instead of using a .htaccess file to get pretty urls for WordPress, you can instead put them in the virtual host config file between <Directory></Directory> tags.
Book review: High Performance MySQL
Kevin Day, October 1st, 2007
High Performance MySQL is a great book for programmers new to database administration who are using MySQL. It has tips on writing faster queries, tuning database parameters, and indexing tables properly. While I had previously stumbled around with EXPLAIN statements and tried to guess what was going on with slow queries, this book demystified how MySQL really works.
This book is most useful for programmers looking for help beyond the standard introductory PHP/MySQL books and tutorials. It assumes that you know how to create a database-driven website but don’t know how to make it faster or deal with high traffic. It also covers the basics of databases such as transactions and index types.
I would have preferred a more detailed description of database tuning because there are a lot of settings to tweak, and it’s not easy to predict how they will work together. The book does provide a decent starting point though, and I now feel comfortable fiddling around with MySQL’s settings until I find the ones that work.
Overall, it’s a good book that will help any programmer using MySQL.
DNS changes don’t have to take so long
Kevin Day, May 30th, 2007I recently read the Wikipedia article on DNS and was surprised to learn that DNS changes don’t have to take 48 – 72 hours like some people say. Although that is approximately the default wait time, there is a parameter in the DNS record called Time To Live (TTL) that controls how long DNS servers cache your DNS record.
An article on NetworkClue.com describes how you can use the TTL to your advantage when moving a site to another server:
So if you plan on ever changing your website IP address for example, it is a good idea to change the TTL of the line(s) that specify the IP address of your website a few days before the change takes place. I would change it to something like 1H (1 hour). Then on the day you move your website to a different IP, the worst case scenario is that someone will be looking at the old address for the next hour.
After the move is complete, change the TTL back to it’s original value. This article on dulcea.com also has advice on changing your DNS record.
I haven’t tried this yet, but I’ll keep it in mind the next time I’m moving a domain.
