Dedicated Server Reviews

If you have a Plesk server where short mail names are enabled, upgrading to Plesk 8.4 can cause some issues. Valid logins may be rejected, and they’ll appear in your /usr/local/psa/var/log/maillog as “no such user”. You can correct the issue by switching to long mail names (click Server -> Mail in Plesk), or you can run a shell script provided by Parallels.

For further details, refer to the Plesk KB article “Mail users cannot get or send mail after upgrade to Plesk 8.4″

As I get started with ruby, one of the things I’ve noticed is that ruby’s documentation could be a bit better.  However, I discovered that this four line ruby script will give your documentation for your server’s installed gems:

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#!/usr/bin/env ruby
require "rubygems/server"
options = {:gemdir => Gem.dir, :port => 4242, :daemon => true}
Gem::Server::run(options)

Thanks to Daniel for the ruby code!

After running sar on my new slice from SliceHost*, I noticed a new column called steal. It’s generally very low on my virtual machine, and I’ve never seen it creep over 1-2%.

IBM’s definition of steal time is actually pretty good:

Steal time is the percentage of time a virtual CPU waits for a real CPU while the hypervisor is servicing another virtual processor.

So, relatively speaking, what does this mean?

A high steal percentage may mean that you may be outgrowing your virtual machine with your hosting company. Other virtual machines may have a larger slice of the CPU’s time and you may need to ask for an upgrade in order to compete. Also, a high steal percentage may mean that your hosting company is overselling virtual machines on your particular server. If you upgrade your virtual machine and your steal percentage doesn’t drop, you may want to seek another provider.

A low steal percentage can mean that your applications are working well with your current virtual machine. Since your VM is not wrestling with other VM’s constantly for CPU time, your VM will be more responsive. This may also suggest that your hosting provider is underselling their servers, which is definitely a good thing.

* I’ve been a customer of SliceHost for a while (prior to Rackspace’s acquisition), and I recommend them to anyone who needs a solid VM solution. If you want to help out with my hosting costs, you’re welcome to use my SliceHost referral link.

One question a lot of soon to be dedicated hosting owners ask themselves is how much should they worry about security with their new dedicated server or hosting plan.  First let me answer your question.

Should you worry?  Yes!  Server security is your responsibility as the server owner. If you don’t know much about dedicated hosting yet though you may ask if your web host has any sort of managed service.  This would put the security upgrades of most important components such as server kernel in the hands of somebody else. Please also be advised, control panel usually make the updates easy to handle, if you don’t have very customized setup.

This may cost a little extra, but is well worth the expense if you are a novice user in the world of dedicated hosting.

I know I usually talk about Linux server related topics on this blog, but I’m pretty proud of what I’ve figured out this morning on my Mac. As you know, the iPhone can really only fully sync with one machine, and if you want to connect it to a new Mac that you’ve purchased, you have to fully erase the iPhone and start over. (Of course, if you used the Migration Assistant to set up your new Mac, this won’t be necessary.)

Here are the steps to migrate your iTunes data from one Mac to another without having to erase and re-sync your iPhone:

• Make sure that iTunes is not running on both Macs.
• Disconnect your iPhone/iPod from both Macs.
• Copy your iTunes folder.
  /Users/username/Music/iTunes
• Copy your iPhone/iPod backups.
  /Users/username/Library/Application Support/MobileSync
• Copy your iTunes configuration files.
  /Users/username/Library/Preferences/com.apple.iTunes*
• Open iTunes on your new Mac and verify that Applications and Ringtones appear.
• Connect your iPhone/iPod to the new Mac and accept any new authorizations.
• Use iTunes on your old Mac to de-authorize the computer.

If you choose to keep your MP3’s separate from iTunes (and not in the library), this will only copy over the references to the MP3 files themselves.