2.2 Add Local Network Storage

Network Storage

Introduction

When on a local network it would be terrible not save on the network but only on the computer. You most likely would place files that everybody on the network would be able to us. For example teachers often share resources and lesson plans so it would be convenient for everybody to have every one can access it.

  1. The most simple way to add shared data space to your network is by using a Network Storage Device, which basically is just a hard drive with an ethernet or USB port.
    • ADVANTAGES -- Very easy to setup (matter of minutes, not hours); does NOT require a computer to serve files; affordable and do not take up much space.
    • DISADVANTAGES -- Some do not use redunadancy (RAID) so they will need to be backed-up; can have slower transfer rates than RAID devices.
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What is RAID?

RAID(redundant array of independent disks) is a system which uses multiple hard drives to share or replicate data among the drives. You would most likely find RAID on servers, more than computers, because it holds massive amounts of data. Servers have a lot of computer users using the network, while computers doesn't. In other words, using RAID is like backing up a server with multiple drives.

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benefits

  • decrease data corruption
  • increase fault tolerance
  • increase disk storage
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RAID 0

RAID 0 is a striped set that splits data evenly across two or more disks with no parity infomation for redundancy. The reason to use RAID 0 beside redundancy is for increased performance. This RAID can be created using different sized storage devices but is only as big as the smallest one. Reliability deceases as the more disk are added. reliability is measured in mean time to failure(MTTF) and to find it,you take the average reliability of each disk divided by the number of disks.

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RAID 1

RAID 1 also called mirroring creates an exact copy of data on two or more disk. The performance of the drives increases the more disks you put in. The computer can read more places in the drive at the same time. The transfer rate of the drives would increase to how many disk you put in.

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RAID 5

RAID 5 uses block-level striping with parity data distributed across all member disks. This RAID is one of the most popular levels due to the security of redundancy.In theory the number of RAID 5 drives can reach unlimited. The downside of using a lot of disks is greater probability of multiple disk failures, longer time to rebuild drive, greater probability of having a error on rebuilds.

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Network Storage

Now that you know the different ways of storing data on a network, you have to understand the devices that use them. Like i said before, it wouldn't be efficient to store data on every computer on the network. There is something called Network-Attached Storage(NAS). Network Attached Storage is storage technology that can be connected directly to a computer network to provide centralized data access and storage to heterogeneous network clients. NAS uses a small operating system that is used only for file serving. NAS have one or more hard disks usually with some kind of RAID. NAS use file protocols such as Network File System (NFS) and Microsoft's Server Message Block / Common Internet File System (SMB/CIFS).

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Advantages

  • Access to data even when the server is down
  • Increased performance due to NAS only for file serving
  • Increased scalability
  • Increased reliability
  • Low cost of NAS appliances
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Disadvantages

  • Shared storage
  • No storage security involving sensitive data
  • Inefficient data transfer