SAN for ALL - Part 1

Posted by bitbud on October 3, 2008 under Bitbud Blog |

SAN for ALL!

The paradigm has shifted (some time ago), and centralized storage is now a requirement for any organization to most efficiently run their infrastructure.  The ability to pool your storage resources, especially as data storage requirements explode, is invaluable.  No longer being tied to how many hard drives a single server can hold, but instead having expandable storage easily accessible via a network.  Today, iSCSI is the standard bearer (sorry FC, AoE), and many organizations see the need for implementing it.  However, the most common roadblock to implementing a SAN…

There are other impediments, but cost is easily the biggest.  It almost hurts to read about such great technology, to work with it in the business world every day, but not be able to afford it for your church.  The features and the capabilities that are gained from a well implemented SAN add so much value to IT, they cannot be ignored.  When IT works more efficiently, that helps them fulfill their role to support the ministries of the Church, which in the end is all that matters.

The cost factor is especially true for a small church (like mine), where there is no IT budget, where the infrastructure is built almost exclusively on donated, older computers.  In those situations, the necessity to be good stewards of limited resources is highlighted.  For a church of any size good stewardship is important, but for a church with no financial resources to contribute to the cause, it seems as there is no opportunity.  But that isn’t the case…

This is for those church’s who see the need for the technology, and have the time, but almost no resources to devote to the effort.  This is also for those that see the need, have the time, and the resources, but want to save some money, and gain a greater level of understanding, experience, and flexibility - the typical DIY-er.  You too can have a SAN, with every feature available to you in commercial SANs, for little to no cost.  The only thing you sacrifice is performance - at least for the SAN that costs nothing.  However performance can be improved to be on par with commercial equivalents for minimal amount of cost.

I’m going to break this down into several posts covering multiple options for configuration, features, costs, and performance.  Let me start with an example:

At my church, I recently implemented a new SAN for $476, using two donated PCs.  You could get by for less $$ if your PCs already have SATA hard disks of the capacity you want, but these were oooolllllddddd computers, so some minor upgrades were needed:

• 4 * 500GB SATA II drives @ $80/ each
• 2 * SATA II 4 port @ $18/ each
• 4 * Intel Gigabit PCI@ $40/ each

So - what did we get for all this?

• approximately 1/2 TB of disk space
• RAID 1 (mirror)
• FT/ HA (fault tolerant/ high availability)
• Dynamic resize
• Snapshot
• multi protocol (we use NFS and iSCSI, you could also use AOE, CIFS, etc)
• encryption
• cuts your grass
• makes your coffee
• …i might have forgotten something

How does it work?  The two PCs are each running 2 500GB drive in a RAID 1.  They are also connected to each other in a network RAID1.  Using HA, they are providing network services(NFS, iSCSI) in a primary/secondary fashion.  Dynamic resize and snapshots are provided via LVM, for the NFS shares I used XFS.

The FT/HA adds a bit more complexity, and may be overkill for many.  The rest of the features though are important.  An alternative to HA would be to simply use the 2nd PC as a backup system of the first, using simple replication.

These system were put in place to support the virtual servers that will be running all the back end systems.

In the next post I’ll go into the details of installing and configuring iSCSI on Ubuntu.