What is a Network Attached Storage device?
A Network Attached Storage (NAS) device is simply put: an external hard drive that users access via a computer network. Peel the NAS onion back a layer and what you have is: one or more hard disks, a network card and a CPU running a minimalist operating system that provides filesystem, networking and file sharing services.
NAS devices come in all shapes and sizes and with all kinds of bells and whistles. NAS devices range in size from 500GB to multiple terabytes. Some NAS devices store data on a single hard drive, other larger NAS devices store data across a Redundant Array of Independent Disks (RAID) which provides protection from data loss due to a hard disk failure. Some NAS devices use no access controls (anonymous), other devices are capable managing user lists internally, other devices can authenticate username/passwords against an Active Directory LDAP database. Some NAS devices only provide file sharing via Windows shares (SMB/CIFS), other NAS devices provide a range of file sharing services including SMB/CIFS, AFP (Apple), NFS (Unix/Linux) FTP, Secure FTP, etc. Fancier NAS devices can even stream video to uPnP devices, act as an iTunes music server, act as an Apple Time Machine backup device and perform automatic backups to/from other computers.
Installing a NAS device, depending on the device, can be as simple as plugging the device into power and a network. Most NAS devices are headless and all configuration changes are made using a web-interface and/or front mounted LCD/keypad. The most common installation steps are reseting the default administrative password and setting the IP address, netmask and gateway.
So how can a NAS be used at sea?
Let’s look at two examples of where a NAS device can solve common data sharing/access problems.
Science party needs to share data with each other:
Has a science party ever asked, “Is there somewhere on the network where we can upload files that everyone else in the science party can access? ” For small groups, setting up a shared folder on somebody’s laptop works ok. However, on Windows XP this only work for groups up to 10 people (Windows XP Home only supports 5 users). Mac and Linux users have it a little bit better but sharing a folder on someone’s personal machine is less than ideal. A better solution is a dedicated machine that doesn’t limit the number of network connections.
So let’s say you you create a shared folder for the science party on one of the vessel’s existing Windows2003/2008 or Linux servers that allows an unlimited number of users. This solves the sharing problem but raises two other concerns: why are the scientist allowed on the same network as the ship’s servers?; what’s stopping the scientists from filling the entire server (which may cause stability issues)?
So what about building a dedicated machine (located on the science party’s network, no the ship’s network ) with shared folders just for the science party. This solves all the problems but now you’ve got another machine to maintain!
Enter the NAS. With a NAS connected to the science party network you have a network folder that is complete independent of any ship-critical systems. The NAS can handle simultaneous access from the entire science party. Installing the NAS involves plugging the device into the network, configurign the IP address for the NAS, writing that IP address up on the lab whiteboard and walking away. No Windows Updates, no user permissions, no additional security concerns. At the end of the cruise simply erase all the data off the NAS and you’re ready for the next trip. Nice and easy!
Science party wants access to data collected by ship’s sensors:
Here’s another common question: “How can I look at the data alerady collected by the ship’s sensors?” Now you could provide the science party with network access to the folder on the ship’s server where the data is collected but that raises the same security issues listed previously plus the added risk that someone might accidentially modify/delete the data.
With a NAS device on the science party’s network, the ETs or STs can use a thumb drive or external hard drive to copy the sensor data from the ship’s server to a folder on the NAS. Now the entire science party has access to the collected data without having to worry about the orignal data being modified. This isn’t the perfect solution. To upload the data to the NAS requires connecting to the science party network via a laptop or workstation. CAUTION: During transfers the thumb drives or external hard drive can be infected with viruses. If you do this be sure when you connect the drive back to the ship’s network that you run an up-to-date virus scan on the drive before using it. However at least with this approach you know where and when the risk occurs and can take the appropriate to protect the ship.
Vendors, Features, Prices, etc
Let’s Compare a Simple NAS device with a traditional external hard drive.
|Device||LaCie D2 500GB||Buffalo LinkStation Live NAS|
|Capacity||500 GB||500 GB|
|Interfaces||Firewire 800, Firewire 400, USB 2.0, eSATA||10/100/1000 Ethernet|
|Number of Users||1 Local, 10 w/Shared folders in WinXP Pro||Unlimited, via network|
|Supported Operating Systems||WinXP/Win2k, Linux, Mac OS X >=1.3.9||WinXP/Win2k, Linux, Mac OS X >=1.3.9|
|Price||$117.00 (google.com/products)||$137.00 (google.com/products)|
The advent of NAS devices provides an elegant mechanism for providing network-based storage for the crew and science party without adding any significant maintenance burdens or security risks to mission critical servers and networks. Adding a NAS device may be as simple plugging it into power and a network switch.
For vessels with transient science parties, a NAS provide an excellent sandbox for users to share their files as well as access copies of ship data without worrying about the science party accessing/modifying any ship-critical files. The right NAS can handle all of your users whether they’re using Windows, Mac or Linux users.
NAS devices are not terribly more expensive the equivalently sized external hard drives and when you factor in the amount of time spent configuring shared folders on a science party member’s laptop or setting up a stand-only sever, a NAS may represent a significant value. As always it a matter of assessing the needs and picking the right tool for the job.