Can I use a NAS with iTunes?

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The DLNA technology standard offered by Digital Living Network Alliance that enables you to easily stream music and video to a stereo or HDTV, print photos from a camera, and transfer files to a mobile device. In order to serve files to other devices, both the NAS and the device that will be receiving the file (either as a stream or as a download) must be DLNA Certified Products.

With Universal Plug and Play (UPnP), devices that are connected to the same network can automatically detect one another for easy sharing of files. A NAS with a UPnP server can easily connect with and stream multimedia to other UPnP-enabled devices, such as game consoles.

While the Wi-Fi-enabled Time Capsule provides a central location for backups for all the Macs in your home, it's technically not a NAS device as it only provides backup and recovery functionality. You can't use it to stream media (i.e., via an iTunes server) or access files remotely.

What is RAID?

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RAID (redundant array of independent disks; originally redundant array of inexpensive disks) utilizes a series of two or more hard drives and either divides or replicates data across them in a number of ways. RAID is a way of storing the same data in different places (thus, redundantly) on multiple hard disks.

By placing data on multiple disks, I/O (input/output) operations can overlap in a balanced way, improving performance. Since multiple disks increases the mean time between failures (MTBF), storing data redundantly also increases fault tolerance.

In a single-user system where large records, such as medical or other scientific images, are stored, the stripes are typically set up to be small (perhaps 512 bytes) so that a single record spans all disks and can be accessed quickly by reading all disks at the same time.

In a multi-user system, better performance requires establishing a stripe wide enough to hold the typical or maximum size record. This allows overlapped disk I/O across drives.

There are at least nine types of RAID plus a non-redundant array (RAID-0):

• RAID-0: This technique has striping but no redundancy of data. It offers the best performance but no fault-tolerance.
• RAID-1: This type is also known as disk mirroring and consists of at least two drives that duplicate the storage of data. There is no striping. Read performance is improved since either disk can be read at the same time. Write performance is the same as for single disk storage. RAID-1 provides the best performance and the best fault-tolerance in a multi-user system.
• RAID-2: This type uses striping across disks with some disks storing error checking and correcting (ECC) information. It has no advantage over RAID-3.
• RAID-3: This type uses striping and dedicates one drive to storing parity information. The embedded error checking (ECC) information is used to detect errors. Data recovery is accomplished by calculating the exclusive OR (XOR) of the information recorded on the other drives. Since an I/O operation addresses all drives at the same time, RAID-3 cannot overlap I/O. For this reason, RAID-3 is best for single-user systems with long record applications.
• RAID-4: This type uses large stripes, which means you can read records from any single drive. This allows you to take advantage of overlapped I/O for read operations. Since all write operations have to update the parity drive, no I/O overlapping is possible. RAID-4 offers no advantage over RAID-5.
• RAID-5: This type includes a rotating parity array, thus addressing the write limitation in RAID-4. Thus, all read and write operations can be overlapped. RAID-5 stores parity information but not redundant data (but parity information can be used to reconstruct data). RAID-5 requires at least three and usually five disks for the array. It's best for multi-user systems in which performance is not critical or which do few write operations.
• RAID-6: This type is similar to RAID-5 but includes a second parity scheme that is distributed across different drives and thus offers extremely high fault- and drive-failure tolerance.
• RAID-7: This type includes a real-time embedded operating system as a controller, caching via a high-speed bus, and other characteristics of a stand-alone computer. One vendor offers this system.
• RAID-10: Combining RAID-0 and RAID-1 is often referred to as RAID-10, which offers higher performance than RAID-1 but at much higher cost. There are two subtypes: In RAID-0+1, data is organized as stripes across multiple disks, and then the striped disk sets are mirrored. In RAID-1+0, the data is mirrored and the mirrors are striped.
• RAID-50 (or RAID-5+0): This type consists of a series of RAID-5 groups and striped in RAID-0 fashion to improve RAID-5 performance without reducing data protection.
• RAID-53 (or RAID-5+3): This type uses striping (in RAID-0 style) for RAID-3's virtual disk blocks. This offers higher performance than RAID-3 but at much higher cost.
• RAID-S (also known as Parity RAID): This is an alternate, proprietary method for striped parity RAID from EMC Symmetrix that is no longer in use on current equipment. It appears to be similar to RAID-5 with some performance enhancements as well as the enhancements that come from having a high-speed disk cache on the disk array.

How much hard drive storage will a NAS provide?

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A NAS device can have either fixed amount of hard drive space or single/multiple hard drive bays that allow you to easily add more hard drives when more storage is needed (or swap out a drive when it becomes full or needs replacing).

A Network Attached Storage with a fixed amount of storage will have either one or two hard drives placed in an enclosure for storage space ranging from 500 GB to 4 TB. This is a good solution for those who are focused primarily on streaming media, or those who want to back up just a couple of computers with small storage capacities.

With the ability to add more hard drive space as needed, a NAS with multiple hard drive bays is a good solution for those with larger multimedia libraries, creative professionals (such as photographers and videographers), and small businesses or homes that require multiple computers to be backed up.

Another advantage of using a NAS with multiple hard drives is the ability to redundantly back up your data over multiple hard drives using RAID.

Tip: Some NAS devices also include one or several USB ports, enabling you to add even more storage via external hard drives. Additionally, depending on the NAS device, the USB port can be used to connect a printer if it includes a built-in print server.

What can a NAS do?

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For those of you who have stumbled over to this section, you may be asking yourselves "what is a NAS"? NAS or Network Attached Storage is is a system consisting of 1 or more hard drives, an Ethernet connection and an operating system.

When it comes to NAS, sharing can mean multiple things. You can share files, share storage capacity and even share a printer. Here's a rundown of features a NAS can provide your home or small business.

• Back Up: Easily and automatically back up and protect content from PCs and Macs. Many NAS devices come with backup software (either proprietary to the manufacturer or commercially available software such as Retrospect). Additionally, some NAS devices are compatible with Apple's Time Machine software, enabling all the Macs in your home to back up to a central location.
• Share Files: With a NAS device centrally located on your network and available to all users connected to your network, everyone in your home or business will have access to documents, photos, videos, music, and more--all without having to turn on another computer to get access to files.
• Stream Media: In addition to storing video, music, and photo files, a NAS device can also stream those files over your network to not only your computers but a wide range of connected devices. For instance, many NAS devices can be used as a server for the Apple iTunes media library software, allowing you to serve up music and video to any computer or device (such as an Apple TV) in your home. And many NAS devices can easily stream music, movies, and more to UPnP and DLNA-certified devices, ranging from HDTVs and set-top boxes to game consoles and mobile phones.
• Remote Access: If you want to grab documents that you left behind at home or your home office, or stream music that you forgot to load into your MP3 player, a NAS device can deliver them to you wherever you might be (as long as you have broadband Internet connection for the NAS and either a Wi-Fi or 3G connection for the remote device). Most NAS devices provide a secure method for connecting your laptop to files stored on the NAS, and more NAS devices are offering apps for Apple and Android-powered mobile devices to remotely access files stored back at home--allowing you to show off.
• Print Server: This gives you the ability to share a printer with all the computers and compatible mobile devices on your network. Just plug the printer into a USB port on the NAS and the printer becomes visible on the network.
• Video/Media Encoding and Downloading: Using the included processor, some NAS devices can encode video files to other codecs--such as converting AVI files to formats that are compatible with Apple's iTunes and iOS devices. Additionally, some NAS devices include the ability to manage and download BitTorrent media files

Hopefully you now have a better understanding of What can a NAS do!.

What do I need to set up a NAS?

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Network Attached Storage (NAS) is essentially a device that connects hard drive storage to your home or small business network and allows that data to be accessed by other computers and devices connected to that network.

You need to have a network router to create a local area network (or LAN) and a computer. The NAS will typically connect to the router via wired Ethernet connection, and then be visible by your computer. At that point, you can run any software set-up that's required (or added software, such as for automatically backing up your computer).

While most NAS devices require an Ethernet connection to your network router, some models offer built-in Wi-Fi wireless connectivity and don't need to be physically connected to a router.

While some NAS devices come with software that needs to be installed on every computer on your network in order for them to access the storage device, many NAS devices don't need any complicated software tweaks. Just connect the NAS device to your network, power it up, and your connected PCs, Macs, and mobile devices will see the NAS on the network and be able to access its files and features.