Network Attached Storage At Home

Transcript

Name: Richting: Rolnr: Date: Emmanuel de Wilde Master Applied Computer Science 95502, evening student 09/12/2011 Network attached storage at home Abstract In this paper, I define Network Attached Storage and explain why it has become popular in recent years. Due to the massive amount of dedicated solutions available for sale, it is not easy to find one that matches your requirements. So I explain some of the most important specifications. Note that this paper does not contain a comparison of existing NAS products, but instead a list of features and why each of these matters. Then it is time to install and configure our NAS. Depending on the confidentiality, importance and desired uptime of the data, several considerations have to be taken into account. Finally, I experiment an open source NAS implementation on a regular pc, and compare that to a dedicated NAS solution. 1. Introduction 1.1. NAS: Definition “Network-attached storage (NAS) is file-level computer data storage connected to a computer network providing data access to heterogeneous clients. NAS not only operates as a file server, but is specialized for this task either by its hardware, software, or configuration of those elements. NAS is often made as a computer appliance – a specialized computer built from the ground up for storing and serving files – rather than simply a general purpose computer being used for the role.” [1] In this paper, each time I use the term “NAS” without other description, I mean a dedicated NAS solution for home use: a network-connected external device containing one or more hard disks, which is not much bigger than the drives it contains. Have a look at the picture on the right for an example. An example of a NAS: Netgear Stora 1.2. NAS vs. other file-sharing solutions The main difference between NAS and Direct-attached storage (DAS) is that DAS is not networked. An example of DAS at home is an external USB disk: It is attached to a single computer at a time, and by consequence cannot easily be shared concurrently among different computers. [2] Note that you can turn an external USB drive into a NAS by using an adapter (USB => RJ45). [3] However, as USB NASes cannot compete with (dedicated) HDD NASes in terms of features and performance, I won’t handle them here. 1 Of course, you can enable File sharing on your computer to enable other users to access specific folders. [4] If several people do this, it means that the shared data is not in a single place: every share has to be configured and backed up separately. The availability of the shared data depends on whether the computer containing it is running or not and how many resources it has left to effectively share data. For example, a game might be so CPU-intensive that the computer cannot serve files at the same time. NAS devices are distinguished from File servers generally in a NAS being a computer appliance – a specialized computer built from the ground up for serving files – rather than a general purpose computer being used for serving files (possibly with other functions). Potential benefits of network-attached storage, compared to non-dedicated file servers, include faster data access, easier administration, simple configuration and lower power consumption. [5] NAS should not be confused with Storage Area Network (SAN), which offers block-based storage and lets the client manage file system concerns. In contrast, NAS uses file-based protocols such as NFS or SMB/CIFS where it is clear that the storage is remote, and computers request a portion of an abstract file rather than a disk block. SAN is essentially used in a professional environment and mostly involves different storage servers working together. [6] 1.3. Is NAS the solution for shared data at home? It is tempting to answer yes: it is more accessible than DAS or file-sharing, easier to use and more effective than a file server, cheaper than a SAN solution. But do these arguments alone explain why dedicated NAS devices became so popular in recent years? There are additional reasons. First, NAS-systems now contain an impressive number of features: you can access them remotely via the internet, they can back up your pc, they have an integrated bittorrent client, they can host dynamic websites with a MySQL database, you can customize them with add-ons, etc. The second reason was valid until summer 2011: the prices for hard disks were really low, you could buy terabytes of storage without ruining yourself. And the consumer needs that kind of capacity because pictures, movies and other kind of data take an increasing amount of space. Finally, the hardware used in NAS systems gradually became more powerful while becoming cheaper. And they consume less power than a normal pc, so it is tempting to leave them on 24 hours a day. [7] 1.4. Should I buy one now? No. Whether they are included or not, you need one or more hard disks in a NAS. Due to floods in Thailand, where essential hard disk parts are produced, the prices of those have more than doubled after summer 2011. At the time of writing, the prices start to decrease gradually, but analysts predict we will have to wait until March 2012 to buy them at their original price. [8] [9] 2 Evolution of the price of a Western Digital 1TB HDD In the meantime, I’ll review the different specifications of NAS solutions and why they matter. Then I’ll explain how to use a NAS. Finally, I’ll conduct some experiments in which I’ll compare a standalone dedicated NAS with FreeNAS (a software NAS server). 2. NAS Specifications: Important Considerations 2.1. Hardware The first decision to make is whether to buy a NAS with hard drive(s) installed (diskful) or without (diskless or BYOD: Bring Your Own Drive). Diskful NASes are usually cheaper, but if a hard drive dies, you have to send the whole NAS back to the factory. Provided it is still under warranty of course, so you might want to check the warranty period before buying. BYOD NASes let you choose which hard drives to install, and you can often add some more later on. However, be advised that each vendor keeps a list of approved hard drives, and you better stick to them. [10] Then, you have the option to buy a single drive or multi-drive RAID product. Whether you choose RAID for added performance or better reliability in case of disk failure, don’t forget that you should always make backups of important data stored on your NAS. A side effect of multidrive NASes is that they are bigger, thereby often have larger cooling fans, which are quieter. The key performance criteria for NASes are read and write throughput. Throughput is affected by three things: NAS performance, Client performance and Network speed. If the client or network connection is slower than the NAS, then you won’t be able to get the full benefit from a very high-performance NAS. If you don’t want your network to be the bottleneck, install a Gigabit Ethernet connection between the NAS and all the clients. Don’t even think about using a wireless connection: that’s even slower than 100 Mbps Ethernet. Finally, you might think it is important that your NAS has a powerful CPU and a lot of memory. Well, it depends on its use: if you plan to host dynamic websites, manipulate media files (e.g. resize pictures), etc., a powerful CPU might help. But keep in mind that those are more expensive, produce more heat and, by consequence, often more noise. A large amount of memory is only useful if you often transfer large files. The performance of the chosen hard drive usually doesn’t matter, as its read/write speed will be superior to the network bandwidth anyway. [11] One of the reasons to prefer a NAS instead of a computer with file-sharing or a file server, is its low power consumption. I recommend choosing a NAS that can turn off or hibernate its hard drives when they are idle. Some NASes can be turned on remotely with Wake-On-LAN, so you can shut them down completely when they are not needed. The housing of a NAS should also be examined closely: - How well does it dissipate heat? Does it cool down the hard drive(s) well enough? Because that greatly affects their lifetime. What is its noise level? (idle & under stress) Does it “feel” solid? I have an external hard drive housing of which the IDE connector broke after a few drive replacements: NOT something you want to happen. Is it beautifully designed or do you have to lock it up in a closet? 3 - Does it have an interface (LEDs will do) to report its current status? Is there an on/off switch? It is not a stupid question: many external USB drives don’t have one. Is there any form of theft protection, like a Kensington lock? Connectivity: is there a USB or eSATA port available for NAS backup, added storage or even USB printers/scanners? 2.2. Features & Software Of course, most buyers will base their choice on the available features. Nowadays, there are plenty to choose from: FTP server, Mail server, Web server, Surveillance station (with IP cameras), DLNA/UPnP Media Server (content to multimedia devices), iTunes server, Print Server, SVN server, Photo & Audio station, Download station (Bittorrent, eMule, …), smartphone compatibility, backup solutions, possibility to add more features with add-ons, … One feature that is really worth investigating is backup: Either you use the NAS as backup, and you can install freeware backup utilities like SyncBack [12] or Cobian Backup [13] on each client. Or the NAS contains data that is not duplicated on the clients, and you need to backup the NAS itself. Some NASes provide a utility to perform the first operation, and almost all of them have an integrated backup solution. Have a look at the “Server Backup” feature of Synology’s DiskStation Manager [14] for instance. The key features you should be looking for are incremental backups (much faster than full-copy), scheduled backups, user-friendly interface and or course, how easy it is to restore data from a backup. Putting data in a box that is connected to a network or even the internet raises the question of security: Is there some kind of firewall to restrict access to the device? Can the NAS become infected with a virus (most run on Linux, so that’s unlikely), and if yes, does it have a virus scanner? Symantec, for instance has developed one: [15]. How is the access control organised: how many users can you configure, and can you group them into common policies? Is it possible to encrypt the data in the NAS? It might seem unnecessary to examine software specifications. After all, as long as the NAS provides the necessary protocols to share its data (SMB/CIFS,…), do you really care how it does it? Well, it might be interesting to know if the software is really getting the most out of its hardware. Is it running a stable OS? What is the support like? Are there firmware updates available in case of trouble? Is there a decent documentation? Can you customize the software to fit your needs? 2.3. Conclusion Finally, there is the matter of price. Even when comparing same spec’ed NASes, their prices often differ substantially. But don’t worry, there are a number of extensive reviews on the Net that can help you make a choice: [11] [16]. As always, try to read a number of user reviews so that you don’t miss any downside of the device you want to buy. 4 Personally, I chose the Synology DS212. It supports 2 hard disks in different RAID configurations, provides an excellent UI, has tons of features, good support, frequent firmware updates, excellent website, good user comments, excellent reviews, low noise (92mm fan), low power consumption when the hard disks are idle, … And I preferred this one instead of the ‘j’ because the extra CPU power (1.6 GHz iso 1.2 GHz) will be welcome for generating thumbnails of my high res pictures, and it has USB 3.0 (iso 2.0) and Wake-On-LAN. Synology DS212 3. How to use a NAS A NAS is basically a computer you connect to your network. Is your network secure? If you have a wireless infrastructure, you should configure it properly (MAC address shortlist, encrypted connection, hidden network name, …) so that your neighbours can’t access it. As most home networks are connected to the internet, you have to realize that it is theoretically possible for an outsider to access your NAS. So the first thing to do is to change the default admin account name and its password (hopefully you have done so for your router already). Make sure there is not a single anonymous access to you NAS, unless absolutely necessary. As always, choosing strong passwords is the key to effective security. You can also physically protect your NAS: put it in a place where it is not likely to be stolen, secure it with a Kensington lock. Schedule it so that it automatically shuts down at night, when you are at work or whenever no one needs it: A NAS that is turned off cannot be hacked (WOL excepted). Make sure its power cord is connected to a surge protector so that it won’t blow at the first thunderstorm. Consider using an UPS if you can’t afford your NAS to shut down unexpectedly, while losing the currently transferred data. Then, you have to evaluate the data you plan to store on the NAS: is it public (internet), public to the private network, private to a group of users or private to a single user? You should set permissions accordingly. Some NASes allow you to define password policies, or use the existing network accounts. You should also decide whether you use the NAS exclusively as backup, or if the NAS contains common data that isn’t duplicated on any other computer. You can combine both of course. If you plan to put sensitive information on your NAS (scans of official documents, pay checks, accountancy of off-shore banking accounts, …) you should consider encryption. Beware: not all NASes provide this feature, and different encryption algorithms exist: you have to find the right balance between confidentiality and performance. There are two ways your data can be stolen from the NAS: either physically by stealing the device or remotely by hacking into your network. If your sensitive data is encrypted, it will at least take them more time to read it, allowing you to do some damage control if needed. In the best case, they won’t be able to decrypt anything. Finally, I strongly recommend having a procedure to decrypt data from a backup if your NAS breaks down or gets stolen. 5 At last word about backups: you should always consider the worst possible scenario: a thief takes all your computers, external drives and removable media; your entire house burns down or gets flooded. If all your backups were at the same place as your computers, you have lost everything. So you should always have a backup at some remote (and secure!) location, and find some way to update this backup without ever having all your data and backups at a single place. So if you use removable media, you need at least two backups. Another option is to have a second NAS at another location, and schedule an automatic backup from your first NAS to it. In all cases, you should verify regularly that you can retrieve all the data from your backup: you don’t want an empty or outdated backup disk when your system crashed. 4. Experiment: FreeNAS vs. Dedicated NAS 4.1. Introduction FreeNAS is a free, open source, Network-Attached Storage operating system based on FreeBSD and supports sharing across Windows, Apple, and UNIX-like systems [17]. FreeNAS features CIFS (Samba), FTP, NFS, rsync, AFP protocols, iSCSI, S.M.A.R.T., local user authentication, and software RAID (0,1,5), with a webbased configuration interface. FreeNAS takes less than 64 MB once installed on CompactFlash, hard drive or USB flash drive. FreeNAS is currently distributed as an ISO image and in source form. Through version 7.x, it was possible to run FreeNAS from a Live CD, with the configuration files stored on an MS-DOS-formatted floppy disk or USB thumb drive [18]. So FreeNAS is purely software, you have to provide some hardware to run it on. Synology DS212 vs. old Pentium III with FreeNAS The Synology DS212, on the other hand, comes with its own hardware. In fact, the hardware is most of the time the only difference between Synology NASes, as they all run the same AJAX-based web interface, called DiskStation Manager (DSM). The operating system is based on a Linux kernel. Windows, Mac OS X and Ubuntu clients are supported via common network protocols (SMB/CIFS, FTP, AFP, NFS, WebDAV), using UTF-8 character encoding for compatibility. Differences between models mainly lie in the amount of performance or storage capacities which are required by the user. Synology NAS units do not ship with hard drives by default; instead customers are presented a list of recommended models/brands. [19] Both units are connected with SFTP Cat6 cables to my Vaio laptop through a Gigabit Linksys switch. Thus, the only bottleneck should be the units themselves. As the process of choosing the right hardware for both of them is worth mentioning, I added their final specifications only in section 4.4. 6 4.2. FreeNAS: Documentation and Installation First, I decided to try FreeNAS. I immediately ran into several problems: There is almost no information whatsoever on the official website. [17] It is, for instance, not immediately clear that there is a huge difference between version 7 and 8. I have the feeling that version 8 is in fact not aimed at the home user: the minimum requirements specify that you need 4 GB of RAM! I might be old-school, but I don’t have a pc to spare with that much memory. Beware that the documentation for these versions are located on different websites: [20] and [21]. I found some other walkthroughs for version 7: [22] and [23]. In my original plans, I would have installed FreeNAS on a CD or a USB key, launch that on my desktop computer, and it would auto-magically detect the existing hard disks and share their contents without erasing them. After a lot of reading, it appeared that the installation of FreeNAS will not only format my USB key, but also format the hard disks you select for storage! It even seems that if you even think of accessing or writing to a FAT32 partition, your data might get corrupt… And setting up a dual boot configuration (FreeNAS, other OS) seems to be as easy as rocket science. As I don’t want to take any risks, I don’t even dare to run FreeNAS on VMWare. After those encouraging words, I decided to have a go on a really old pc, which I don’t really care about. Have a look at section 4.4 if you are interested in its specifications. The computer has a single, 30GB IDE hard drive. As I mentioned above, it’s not the hard drive that will be the bottleneck, but the network card: it is an old 100Mbit version, which will restrict transfer rate to maximum 12 MB/sec. The old pc contains a working Windows 2000 installation which could be handy as backup if another pc breaks down. As I had no guarantees that FreeNAS would not wipe out all existing partitions on the hard drive, I took some precautions. First I backed up all data I could still care about (I’ll examine it later), then I defragmented the Windows partition, and took an image of it with a CloneZilla FreeNAS installation: picture of the instructions boot CD. [24] [25] CloneZilla took an awful lot of time to complete, but did write the image on my external hard drive. I was finally ready to install FreeNAS. First I launched the bootable LiveCD, and after some configuration (choosing keyboard layout, …) it worked immediately: The screen printed out its IP address, and I could surf to the FreeNAS UI (called WebGUI) with my laptop. As nothing has been modified on the hard drive yet, the configuration is stored on a floppy disk. In order to avoid the annoying configuration steps at each boot, you have to insert the floppy disk right after FreeNAS has started booting… which is impractical and slow. 7 So I installed the full version (not the embedded) of FreeNAS with partitions for the operating system, the swap and the shared data. At the end of the procedure, FreeNAS required to reboot, after which I had to complete some steps in the WebGUI. Unfortunately, I found no other way to keep a copy of those instructions (configure swap and data partition) than to take a picture of the last screen. Anyway, FreeNAS ran fine after the reboot, and after setting up a Disk, a Mount Point and an anonymous Share, I could finally start to use it: The share appeared automatically in Windows Explorer > Network > FREENAS. I tried to copy a first file to it, and it worked! FreeNAS WebGUI: System Status 4.3. Synology DS212: Unpacking and Installation First impressions after unpacking: The power cord has a reasonable length (which is almost surprising these days), the housing gives a reassuring feeling of solidity, installing a hard drive is really easy (the screws are provided) and they even supplied a network cable! The 92mm fan seems upmarket, which is verified when I turn the device on: it barely makes any noise. As I mentioned in the introduction, hard disks are relatively expensive right now. So instead of buying a new one, I installed the standard 500GB 2.5” 5400rpm SATA drive from my Vaio laptop. It is in fact really suitable for a NAS, as it produces less heat than a 3.5” or a 7200rpm model. And I didn’t use it any more since I replaced it by a SSD drive in the Vaio. Note that the DS212 supports both 2.5” and 3.5” drives. Next I had to use the Synology Assistant to install the DSM on my NAS. This is done remotely, as you can’t connect a screen or keyboard to the device itself. My first attempt failed, because the firewall on my laptop blocked some requests. With that solved, the installation completed successfully. One remark however: The installation of the Synology assistant and DSM doesn’t always respect the chosen language, and is poorly translated. Luckily, the applications themselves are fine. The Synology Assistant 8 With the Synology assistant, you can detect Synology NASes in your network, without knowing their IP-address. You can easily map shares on network drives in Windows, and you can set up Wake-On-LAN. However, this feature only seems to work if you shut down the NAS using the user interface, not if you physically press the power button. You can also launch a memory test on the NAS, but there is no user-friendly way of retrieving the results, which is pretty frustrating given the time the test takes. The Resource Monitor looks like the Performance tab in Windows Task Manager. Finally, the Photo Uploader is really useful if you plan to use the Photo Station (which is a kind of web album application with all pictures put in a dedicated folder): it uses the client’s processor to resize all pictures to thumbnails, which is immensely faster than letting the NAS do the job. Finally, by “connecting” to the selected NAS, you can launch the DiskStation Manager (DSM). Probably the best way to visualize the DSM is to see it as a remote desktop on the NAS: it is really like a complete operating system. You can set up users and groups, shared folders, a firewall, scheduled boot and shutdown, even a Web, FTP and mail server! And you have a wide range of applications to manage all kinds of Synology DiskStation Manager media (music, photos, movies, …). The only thing it doesn’t do yet is coffee, but I’m working on that. Note that all this functionality is already present and is configurable via the user-friendly DSM. If you need some explanation, there is a complete 163 pages manual available, in colour with screenshots. So you do get something for your money. 4.4. Hardware specifications: comparison CPU Memory Hard Drive Network Interface Pentium III 735MHz 300MB SDRAM 3.5” 30GB 7200rpm IDE 100Mbit DS212 1.6GHz 256MB DDR3 2.5” 500GB 5400rpm SATA 1Gbit 4.5. Tests  Network share Both FreeNAS and the DS212 got their most important job done: sharing a drive on the network. Using the DSM, it is really easy to configure users and groups, and give them access rights to the different shared folders. Setting up users and groups is equally easy in FreeNAS, but it is not immediately clear how to restrict access to only specific shared folders. Users don’t even seem to have their own “/home” folder as standard. 9  Wake-On-Lan A piece of cake with the Synology Assistant (as described above), but it’s another matter with FreeNAS: This feature doesn’t appear in the WebGUI, the official documentation states that there are as many versions of FreeNAS that support WOL as not, the official FAQ links to an old forum thread with a man page that doesn’t exist. It looks like you have to manually download and install an additional BSD module: [26].  Print Server It looked extremely easy to connect my old HP Deskjet 5550 to my laptop through the DS212: But I did manage to pick the wrong driver in the Synology Assistant the first time, and then I could print from notepad, but not from Word. This issue was caused by Avast! Antivirus, whose shields blocked the communication between the Word process and the DS212. Eventually, my printer works fine though, and I can easily switch computers without having to move the USB cable each time. Next I wanted to setup FreeNAS as a print server. Easier said than done: no information in the WebGUI, the official documentation says it is possible, but it links to different forum threads again: [27]. If you ever tried to install packages on Linux, some memories should pop up while reading those threads: connect to FreeNAS as root with Putty using ssh, browse to a specific dir, download a package that no-one thought of providing as standard, unpack and install it, edit some text files that look horribly complex and that will crash the entire system if you get a single character wrong, change access rights to them, reboot and pray. Even when the procedure is nicely written with some screenshots [28], it still doesn’t look 21st century to me.  Performance I know it is not entirely fair to compare both: the computer on which FreeNAS is installed has to rely on an old 100Mbit network card to transfer data, which will be a huge limiting factor. But let’s do it anyway to get an idea: Average speed FreeNAS DS212 1 large file of 4.5GB Reading Writing 10 MB/s 11 MB/s 63 MB/s 60 MB/s 1500 files with total of 3.7MB Reading Writing 23 KB/s 25 KB/s 54 KB/s 72 KB/s The 1500 files are a part of a modest Java project with a lot of .svn files and folders. The results suggest that you better deploy a real subversion server on your NAS than to back up the sources manually. This can be done on both devices, but does require installing packages manually using the command line interface.  Encryption One of the permanent restrictions of FreeNAS is that it is not possible to encrypt a disk partition, only complete disks are supported. [29] In Synology’s DSM however, you can encrypt specific shared folders: So you can have encrypted and non-encrypted folders sideby-side, on the same partition. 10 4.6. FreeNAS vs. DS212: Conclusion FreeNAS is supposed to be the cheapest solution, as you can run it on some old hardware. As I demonstrated, my old Pentium III is far from optimal: it makes too much noise, has a slow network card and a small hard drive. If I want optimal performance, I should replace the network card, but finding IDE hard drives with more than 300GB seems tricky nowadays; thus I should buy a PCI SATA converter card. For better reliability (the computer is more than 10 years old!), I should also replace the processor fan, and ideally replace the power supply. Now I’ve got something as fast and reliable as my DS212, but at which price? FreeNAS is a really useful free product. But as most applications based on Linux (or FreeBSD), it lacks the user-friendliness needed to make it popular. You should not need to have a degree in computer science to turn FreeNAS into a print server. And as a lot of open source projects, the documentation is incomplete and outdated, which doesn’t inspire confidence. But there is a skilful community online to help you when you’re in trouble. On the other hand, the DS212 is not free. With nearly 300 euros without any hard drive, you can almost call it expensive. But you get a lot in return: reliable, compact hardware; extremely well documented installation procedures; a complete, full colour, up-to-date manual with screenshots; a user-friendly and efficient NAS user interface; regularly updated firmware that works; online support and a lot of eye candy that makes you forgive them for taking your money. And all this is probably true for NASes of other brands than Synology. So which one should you choose? It all depends on you actually: if you can get your hands on an old but reliable computer, you’ve got some time to spare and you like messing around in FreeBSD, go for FreeNAS. But if you’re a working student that doesn’t mind paying to get a solution that works immediately and doesn’t require much maintenance, a commercial standalone NAS like the DS212 is probably a better choice. 5. Conclusion In this paper, I defined Network attached storage and compared it briefly to other file-sharing solutions. I explained why it is interesting to have a dedicated NAS device at home, and I covered some of its most important specifications: You should remember that a NAS can be diskful or diskless, single-drive or multi-drive. In the last case, you can choose from different RAID configurations, but none of those will exempt you from taking backups regularly. And if you want to get the most out of your NAS, you should connect it to a Gigabit network. Concerning software, most NASes come with so many features, that it is difficult to find one they don’t contain. Finally, I compared FreeNAS on an old Pentium III with the Synology DS212. FreeNAS works well, but it is lacking decent documentation. And if you want additional features (print server, WOL, encrypted shares), you get the impression that FreeNAS is somehow not mature yet. The DS212, on the other hand, is a commercial, well build product that does what it advertises. It is not cheap, but it will get the job done in a lot less time and frustration than FreeNAS. Sometimes, that is all that matters. 11 6. 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Whitson Gordon, 19-07-2011. http://lifehacker.com/5822590/turn-an-old-computer-into-a-networked-backupstreaming-or-torrenting-machine-with-freenas [24] CloneZilla. http://www.clonezilla.org/ [25] Wikipedia: CloneZilla. 08-12-2011. http://en.wikipedia.org/wiki/Clonezilla [26] FreeNAS FAQ: Is it possible to send Wake-On-LAN commands or packets from FreeNAS? http://wiki.freenas.org/faq:0144 [27] FreeNAS FAQ: Can FreeNAS act as a print server? 03-03-2011. http://wiki.freenas.org/faq:0004?s[]=printer [28] Instructables: FreeNAS as a Print Server. Tau_Zero, retrieved 01-2012. http://www.instructables.com/id/FreeNAS-as-a-Print-Server/?ALLSTEPS [29] FreeNAS wiki: Setup and user guide: Disk encryption. 03-03-2011. http://wiki.freenas.org/documentation:setup_and_user_guide:disk_encryption [30] Instructables: Build an inexpensive Ikea NAS/Computer. Aaron Eiche, 31-03-2009. http://www.instructables.com/id/Build-an-inexpensive-Ikea-NAS/ 13