Open Source Storage Area Network–Part 1


In this multi-part blog post, I will be going over setting up a custom built Storage Area Network (SAN). In the commercial world, there are many different storage options from companies like NetApp, EMC, and Dell. Each of these companies has great strength when it comes to a SAN, but all have a downside when it comes to a small business or an IT professional wishing to learn more about the technology. That is that they cost a lot of money to acquire, set up, and support. There are some situations where spending a large amount of money may not be possible. That is where this guide comes in.

Like many IT professionals, I want to play around with various technologies at home, but do not have the budget to buy the latest or the greatest all the time. A SAN is one of these technologies in particular. I started looking into options to get as close to a professional SAN as possible. I discovered that there are many options out there that provide many of the features that commercial SAN solutions provide. In the discovery process, I found that some of the options would also work for a small business or test lab for a company.

One of the most important things to building a SAN is the hardware, but in this part of the guide, I will go over the Operating System. The Operating System determines the functionality that will be available such as iSCSI, CIFS, SMB, Fibre Channel, etc… I will only go over a few in this article.

Operating Systems

The few free and open source Operating Systems I have come across are listed below. Each one has some strengths and weaknesses. Please note that for this project, I am comparing these options for the purposes of a SAN and not a NAS. The difference between the two is outside the scope of this guide. As such, there are some features of these systems that are not covered under my review.

I have not installed or used most of these systems, but base all my reviews off the feature list, screenshots, and views of others on the internet. There are also many non-free operating systems that are much better, but the purpose of this guide is to find an open source solution.

OpenFiler

OpenFiler is a very feature rich SAN Operating System. Unfortunately, there are plugins that enhance functionality that are not free. OpenFiler is a great product for an experienced IT professional who is just getting started with SANs and doesn’t know a lot about Linux, but wants full featured capabilities from their SAN including high availability.

I give OpenFiler a difficulty of intermediate because it still requires knowledge about iSCSI configurations and use of the CLI to configure settings for Fibre Channel. Throughout the web interface there are references to Linux terminology. I give OpenFiler a rating of 2 because it is a very straightforward product, but it is based on a dated Linux distribution called rPath and it seems to have stagnated in development because rPath is no longer maintained.

Advantages

  • iSCSI
  • Fibre Channel
  • CIFS
  • NFS
  • Snapshots
  • Web Management Interface
  • High Availability

Disadvantages

  • Community Supported or Paid Support
  • Fiber Channel requires CLI configuration or purchase of plugin
  • Linux 2.6 Kernel (Latest for Linux is 3.5+)
  • rPath Linux is no longer distributed or supported

FreeNAS

FreeNAS is a fantastic Operating System for network storage. There are great features such as snapshots and thin provisioning. The interface is very intuitive and easy to use and FreeNAS is constantly being worked on and updated. For the average user, everything should be very manageable from the web interface.

FreeNAS is also given a difficulty of intermediate because you still end up needing to know iSCSI and other various Unix style terminology when setting up new disks and shares. I give FreeNAS a rating of 3 because it has a fantastic interface, but it is based on FreeBSD and that means a little extra work for someone who has never used FreeBSD. This is only because some of the commands and programs for management are slightly different from Linux distributions.

Advantages

  • Thin Provisioning
  • SMB/CIFS
  • NFS
  • iSCSI
  • Support for 10GbE Network Cards

Disadvantages

  • Uses istgt for iSCSI (Explained in part 2)
  • Based on FreeBSD
  • Community Supported or Paid Support

OpenMediaVault

OpenMediaVault is a feature rich NAS Operating System. There is a plugin for iSCSI targets that allows it to be a SAN, but it takes some work to get it installed. It would be great as a NAS box or using NFS for VMWare, but other users warn that the iSCSI implementation could be a lot better or that they have issues with iSCSI and VMWare.

I give OpenMediaVault a difficulty of Intermediate because the GUI has a vast number of settings and uses Linux terminology. I give it a rating of 2 because of their limited support for being a SAN as opposed to a NAS. iSCSI is limited and requires more advanced configurations to install compared to other plugins.

Advantages

  • Granular ACLs on Shares
  • SMB/CIFS
  • NFS
  • iSCSI

Disadvantages

  • iSCSI Requires Complex Setup 
  • Community Supported

Ubuntu Server 12.10

Using Ubuntu Server, I can customize the packages that I would like. This allows me to have complete control over the features that I need. It also means that I can reduce the footprint and optimize the speed of operations. Although I chose Ubuntu, there are other options like OpenSuSE and Fedora. The only requirement for this option (using this guide) is Linux with kernel version 3.5 or newer.

This option is the most advanced option because we are installing all the required features after installing the operating system. There is no management interface other than the command line. Theoretically I can install a GUI and do some options, but for the most part, this system will be managed with SSH. I give this option a rating of 4 because it is completely tailored to my specific needs and allows me to choose the best packages for the features I need. The downside is that I require the most knowledge of all the options to manage the system.

Advantages

  • Purpose Customized Operating System
  • iSCSI Targets
  • Fibre Channel over Ethernet
  • Fibre Channel

Disadvantages

  • Requires Time to Set Up 
  • Community Supported (Per Package)

Conclusion

For my purposes, I decided to go with building out a SAN based off of Ubuntu. I could have picked any flavor of Linux as long as it runs at least the 3.5 kernel. I chose Ubuntu in specific because that is the flavor of Linux I have the most experience with.

Following my guide, you should expect to have a fully functioning SAN with features like iSCSI and Fibre Channel that you can use to run virtual machines or host mass quantities of storage. From there you can then connect to VMWare or Hyper-V among other systems.

In my next article, I will go over the requirements for building out the OS in more detail along with the packages I am using. I encourage everyone reading this article to look at all the various options before settling on a specific option.

Advertisements

One Response to Open Source Storage Area Network–Part 1

  1. Pingback: Open Source Storage Area Network–Part 2 | Thomas Yates - Tech Blog

Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: