Nov 1, 2008 12:00 PM
Data is a precious thing and will last longer than the systems themselves.
� Tim Berners-Lee
Without a doubt, we rely on data in virtually every facet of business and even in our personal lives. Music, pictures, video, financial data, e-mail � the list goes on. How this data is stored is largely determined by how critical the data is to the organization (or individual), and how long it takes to restore the data. Let's face it, in our society all data is critical, whether it contains corporate financial information or family pictures and videos.
There are numerous published statistics, but the bottom line is that it is inevitable you will experience a failure causing a partial or total loss of data. In a broadcast environment, this could also mean interruption, or possibly complete loss of programming content. The good news is that there are several effective methods to back up data and the cost to implement some of them are well within the budget of a small business or individual.
The storage-area network (SAN) is the best solution from a data recovery and high availability standpoint, but it is also the most expensive and complex to implement. It is defined as a high-speed network of storage elements. In simple terms, imagine you have a PC with its hard drive located somewhere else. While you could achieve this over a traditional Ethernet network, performance and reliability would certainly be compromised due to constraints imposed by common networking technologies. SANs are dedicated high-speed networks optimized to transfer data with high reliability and very low latency.
A minimum SAN is comprised of an array of storage devices interconnected to a server through two SAN switches.
The SAN data is transported over a network called the fabric. A basic SAN utilizes at least two fabrics, essentially two diverse network paths for redundancy. The real power of a SAN is that the fabric can consist of virtually any of the common transport methods utilized in traditional networking; however, the most common implementation utilizes optical-based fibre channel. It is also possible to locate the storage devices off-site using some form of Layer 2 protocol-based wide area network (WAN) transport technology such as ATM, Sonet, T1/T3, DSL, ADSL, etc. WANs utilizing frame relay would not be a good choice as it utilizes the Layer 1 protocol and, as such, is subject to delays and possible loss of data integrity.
Hardware devices called host bus adapters (HBA) are added to the servers. HBA provide the interface between the fabric and the server, as well as facilitating any digital (i.e. optical to digital) conversion processes. In addition, the storage devices utilize a storage processor (SP), which handles all the interfacing tasks between the storage device and the fabric. The SP also manages the configuration of the disk arrays within the storage device.
Due to the fast access, high reliability and high availability of a SAN, chances are you may already have a SAN-based disk arrays as part of your audio storage system.
If the SAN is connected with an optical fibre-channel backbone, the system will also benefit from the natural isolation from lightning and other electromagnetic induced disturbances found with copper cable systems.
Nov 1, 2008 12:00 PM
Network-attached storage (NAS) is the easiest and cheapest method to implement dedicated shared network storage. As the name implies, NAS is simply a server exclusively dedicated to file sharing across a network.
The server in this case can be as simple as an old PC configured with the operating system, or a stand-alone device housing a single disk drive or array of drives. It also serves to manage the network connection and user access functions.
The cost of dedicated NAS has dropped significantly over the past two years. It is not unusual to see NAS devices with 1 terabyte (TB) of storage for under $800. There are a number of different flavors of these devices, including those that provide everything but the disk drives. These are good choices, if you want to select your favorite drive type or already have some unused drives that can be repurposed. These frames may permit a mixture of 3.5" and 2.5" drives; however, most are designed for one or the other type only. Also pay attention to the interface types supported; for example, most new NAS devices support SATA or SCSI, but older IDE interfaces may not work. Setting up one of these NAS devices is fairly simple: assign an IP address, define user access rules and make sure the appropriate PCs on the network are configured properly to see the drives. If the network has a firewall configured, you may also need to open up the appropriate IP address and ports as necessary.
Now, let's say you have little or no budget, but still need to have some network-attached storage. Look no further than your stash of older PCs taken out of service. Did you know these make excellent NAS devices? Yes, you could always set up the file sharing on an unused (or even a used) PC so files can/are/will be shared with others across the network, but this has problems: 1) The PC operating system is managing a number of functions, not just the file sharing, therefore the end result of being slow, 2) If someone else is also using that PC, it gets even slower, and 3) PC operating systems tend to lock up easily when memory resources are taxed, thus access to the drives will be impossible.
The solution to this problem is to reformat the drive in that PC and load a dedicated NAS operating system. There are several of these to choose from and most are free. A program called Free NAS can be downloaded at www.freenas.org; this is one of several open source programs that turn a PC into a dedicated file server. Others include Open Filer (www.openfiler.com), Sun Open Storage (www.sun.com/storage/openstorage) and NAS Lite (www.serverelements.com).
Most of my current projects require that I setup a temporary office when managing large deployments of cell towers. I use Free NAS to enable file sharing and storing of project data between my contractors, customer and other disciplines with excellent results. The actual network operating system is very small and can fit on a flash drive, or any other drive for that matter. You can use just about any PC (Pentium 2 or higher recommended) with a minimum of 96MB of RAM. If you want higher performance, or will have more users accessing the server, it is recommended that you use a more current processor and increase the RAM. Free NAS, as well as most of the other open NAS software, also supports multiple drive configurations including RAID. Setup is a breeze and it works great! The documentation is well written and will get you started quickly.
Here is an idea: if you have a laptop or two sitting around (P2 or higher,) reconfigure them with Free NAS. Then you can load them with all (or portions) of your music library. They could be used along with a network of other laptops to create an emergency backup in the event your facility suffers extreme damage. This type of network can also be used for long term remotes where having data handled on a local server might make sense, i.e. database for a telethon, bit libraries.
Nov 1, 2008 12:00 PM
While the subject of data recovery can fill a separate article, you should be aware there are methods to recover data that go well beyond commonly available recovery software. This software may be effective on data that has not been overwritten with other data and on drives that have not suffered physical damage. Beyond that circumstance, you should be aware that there are companies that specialize in repairing hardware damage such as replacing new heads, drive electronics, servos, etc. For more complex repairs a few companies specialize in forensic recovery of information. These are the same companies used by the government to gather information from drives so they can prosecute bad guys. They are expensive and not 100 percent likely to be successful, but if you really need to get the data, it may be worth the expense.
One final note, make sure your drives are formatted as NTFS or XFS, as opposed to the traditional Fat 32 format. These formats utilize a concept called journaling, which create restore points over time. You may be able to roll-back these drives to a point before the crash occurred, thus only losing data from the current day back to the restore point.
The bottom line here is to make sure you have a good backup system and make sure there is a process in place to ensure the backups are timely and the integrity of the backup data is routinely checked.
McNamara is president of Applied Wireless, Cape Coral, FL.