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Network Attached Storage

Submitted by Peter on Wed, 2010-02-03 14:03

There are times when you just want to store some files away from your computer just in case something happens. Way back in the previous century you would use an FTP server for the storage. Today you use NAS, Network Attached Storage. Tomorrow you might store the files in a Cloud.

Up in the Clouds?

Cloud computing is currently free because a few suppliers are trying to swamp the market then they hit you with fees to access your data or because your data grew beyond a tiny limit. Most people live outside America and most clouds are inside America which means the cloud owners do not have to obey your laws. They own your data. They can search it for anything they want. They can sell your files to the highest bidder. They will share your files with all the paranoid spy agencies in America.

You cannot take the information provided by your customers under a privacy agreement then had the data to a totally uncontrolled third party. Cloud computing and storage is out.

NAS

NAS is Network Attached Storage and is little more than an intelligent disk connected to your computer through your network. The advantages are many. You control the storage of your data. You can place the NAS device anywhere there is a network. The device contains a computer to connect to different operating systems and file systems, giving you the option to transfer files from Windows to Linux to Apple Mac via the NAS.

NAS boxes now have many names due to slight differences in the way they connect. Sales and marketing people love to find a trivial or useless difference in their product then give it a spectacular name. The NAS boxes contain one or more disks to store data, a network card to connect to the network, and a processor to move data between the two. Most NAS boxes have a processor that is too slow for the job but a few recent models have decent processors at a reasonable price.

You can build your own NAS using a spare computer case, an old disk, a retired motherboard with a processor and memory, plus a network card. Yes, you can use the six year old computer you gave to your children before they demanded a Playstation. A six year old computer has a hard disk that is a year too old to be reliable and will be too small to store anything useful. Consider it just a practice device.

You will need a big new disk and new disks connect through SATA, which means you need a computer less than six years old. Use the three year old computer you gave to your husband when you purchased your new ASUS notebook with the smooth leather finish. A three year old computer will be as fast as a reasonably priced NAS box and will be compatible with NAS software. Use FreeNAS or equivalent as the operating system.

When you store data on disk, you need space, speed, and security.

Space

Disk space used to be measured in megabytes, MB, with one MB containing a million characters. A popular comparison used to be 500 typed pages because lots of sales people quoted a myth about typed pages containing 2000 characters. MB was replaced with GB, a gigabyte or one thousand MB with current common economy disk drives containing 160 GB and middle range disks containing 500 GB.

The top of the range disks contain 2000 GB which is two terabyte or 2 TB. A TB might contain five hundred million, 500,000,000, types pages but is more likely to contain a few hundred video files. A single sided DVD contains about 4 GB of movie and 0.7 GB of junk, mostly advertising. You can fit 250 of those movies in a TB when you remove the junk.

The new high definition movies contain four times the visual information combined with the same amount of audio information and you can expect to store about a hundred high definition movies in a TB. Common desktop computers can fit four disks for a total capacity of eight TB or four thousand million of the mythical typed pages.

NAS storage can store unlimited information on your network at a low cost. Space is unlikely to be the deciding factor.

Speed

Data is useless if you cannot read the data in a reasonable time. When you watch a movie, the data has to arrive at you screen at least as fast as required to make the movie lifelike. When you watch the same movie the second time and skip some of the boring bits, you want the data arriving two or three times faster than normal so you can skip the boring bits in a reasonable time. Modern disks can perform both tasks easily and modern gigabit networks can carry the same load without problems.

When you search large amounts of data for specific text, speed becomes proportional to the about of data you search. A two minute search might be acceptable but a ten minute search might make your work too slow to keep up with customer requests. When your data doubles in size, you may be able to wait four minutes instead of two minutes but ten minutes is still unacceptable. A few months later when your data doubles, you have to wait eight minutes instead of four minutes for a full search. A few months after that, your data has doubled again, a search has expanded from eight minutes to sixteen minutes, but customers hang up after ten minutes.

When you have large amounts of data and the data increases in size, you want the same access speed to watch a video but you want faster access to perform a search in the same time. Your approach to data storage is a balance between the low cost of adding more storage at the same speed and the high cost of adding more storage at an increased speed.

NAS is forever limited to the speed of your network and network speed is not increasing as fast as storage space expands. Yyou may reach the point where your network cannot deliver the data fast enough to satisfy your requirements and you have to replace NAS with other types of storage that are far more expensive. Network speed is always a limiting factor with NAS.

Security

Security of data has two aspects. The first is ensuring the data is not changed by people who do not care about the data or people who might want to deliberately falsify the information. The second form of security is to ensure the data is there when you need it.

Data availability includes recovering the data despite broken disks and keeping the data online after a power failure. These factors determine the way you store data within a NAS device and they are exactly the same considerations you meet when deciding how to store data on a desktop computer or a server. You should look at backup, RAID, and recoverability.

FTP

FTP was around when Noah put barcodes on the animals walking onto his ark. FTP is one of the oldest living things in the computing world because it works.

NAS devices replace FTP because the overhead of operating a dedicated FTP is greater than a NAS device and an FTP server is not as flexible. Most NAS boxes have FTP as an option along with more modern connections. When you build you own NAS box, make sure you activate FTP.

Linux

Did you shudder when I mention installing Unix? You probably want something easier to install. Ubuntu is probably the easiest version of Linux to install and gives you the same facilities with a better interface. You can set up a NAS box using Ubuntu, most other distributions of Linux, and most versions of Unix.

I suggest you install Ubuntu as a desktop computer and learn to use Ubuntu then install file sharing options including Samba and FTP. There are preconfigured NAS systems based on Linux but you cannot practice using them as a desktop computer.

Conclusion

NAS could be a great way to recycle old computers as backup storage if you have time to learn how to use FreeNAS or equivalent and have a compatible computer. Linux users find it easier to convert their favourite Linux distribution to a NAS system and they will have a wider range of hardware compatibility. Windows users will find Ubuntu the easiest Linux to learn and a better starting point to build their first NAS. If you do not have the time to install software, use a prebuilt NAS box but do not expect fast access from anything cheap.

Further reading