Infopackets Back Online; New Server, and More!, Part 2

... continued from Part 1: Infopackets Back Online; New Server, and More!

Once XenServer was installed on my machine by my hosting company, I had to install a program called 'XenCenter' on my Windows machine which allowed me to access my XenServer using a Graphical User Interface (GUI) over an encrypted virtual private network (VPN).

Once I've got access to my XenServer, I could install virtual machines running any operating system I want (Linux, Windows, for example) and connect them to the Internet and use them as servers.

The Old Server Setup vs The New Server Setup

The old server setup (ordered in 2005) consisted of 2 x dual-core Intel Xeon processors @ 2.4 GHz (2 processors x 2 cores = 4 cores total). This was like having 4 CPUs. It had 2 gigabytes of RAM and 2 x 73GIG SCSI 10,000 RPM hard drives. It was pretty cutting edge at the time and is still a relatively powerful machine.

The new server (ordered in 2011) consists of a single quad core Intel Xeon 1270 @ 3.4 GHz with 2 threads per core (it's like having 8 CPUs, sort of). It has 4 gigabytes of RAM and 2 x 15,000 RPM 300GB hard drives running in RAID 1 + a single 2TB drive for a storage repository. This thing is smoking fast!

Having the 300GB drives in RAID 1 means that if 1 drive dies, it can be detached and replaced with a new drive, and it will rebuild itself on its own with no down time.

This is referred to as real-time backup using RAID 1 format or "mirroring".

Server Virtualization: Major Advantages

There are many advantages why I chose to use XenServer for Infopackets. A few off the top of my head:

The virtual machines I have set up run in near-native speeds as a regular computer. This has to do mostly with the hardware I have, but also because the hypervisor (XenServer) is incredibly efficient; also, the kernel and operating system features (EXT4 file system, for example) I chose have a lot to do with performance.

With my current setup, I can make instant 'snapshots' ("backups") of any of my virtual machines, and revert them to a previous state any time I need to -- much like disk imaging backups. This is *hugely* important, especially in terms of software / server development. I did not have this feature with the last web server.

Speaking of the last web server: I can't tell you how many times I initiated a command from the command line and messed something up, caused the web server to stop responding, and then had to sit there in a panic until it was fixed. No more!

Now, I can simply use a development server (keeping it away from the main system), and revert my changes instantly without wasting time trying to fix it.

Scalability / Moving Virtual Machines with 1 File

One of the coolest parts of using a virtual machine setup like this is the fact that the virtual machines are portable. Essentially, I can take a virtual machine (which actually consists of a single file, and inside of it, all the operating system and user files) and move the virtual machine to another XenServer (a faster one, for example) with no down time.

In other words, I wouldn't have to reconfigure my new web server every time I upgrade my hardware -- I simply move it from one physical machine to the next. This is an extremely powerful idea.

With a traditional hardware upgrade, I'd have to do all the stuff I did over the course of 4 weeks (such as move all the files over, reinstall the operating system, software, etc). But now, I simply shut down the server, move 1 file, and start up the virtual machine, and I'm done.

I can even add more server hardware (a new PC) to my XenCenter hosts and effectively move virtual machines around on different hardware to lessen loads (if I had to).

Of course, at some point I will want to load a new operating system on the server and will be forced to do a complete reinstall -- because at some point, the current OS running on the server will be out of date. But at least this time around, I can prepare for it and work on it in a virtual environment, and set it live when I'm ready without so much stress.

That's all for now! I still have lots of programming to do.

- Dennis