Newbie question on speeds with NAS

Offloading HDDs and other functions to remote NAS or servers is increasingly popular
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Ubtree
Posts: 34
Joined: Sun Jul 31, 2005 4:33 am
Location: United Kingdom

Newbie question on speeds with NAS

Post by Ubtree » Tue Dec 04, 2012 2:53 am

I would really appreciate a brief explanation of how file transfer speeds across a Gigabit LAN (with Billion BIPAC 7800N router) to an NAS equipped with 1TB Velociraptors would compare with the speed of accessing files held on an internal Velociraptor. (Although the headline 1GB speed for the network is much greater than the drives' burst and transfer rates, I suspect that factors that are beyond my limited knowledge - such as real-life network speeds and cache speeds - would have a major impact.)

washu
Posts: 571
Joined: Thu Nov 19, 2009 10:20 am
Location: Ottawa

Re: Newbie question on speeds with NAS

Post by washu » Tue Dec 04, 2012 6:30 am

You are misunderstanding a bit. Hard drive speeds are often rated in mega bytes per second. Network speeds are always rated in mega or giga bits per second. To convert bits to bytes you need to divide by 8. A 1 Gb network is 125 mega bytes (MB) per second. Using that number to compare, a modern velociraptor is faster.

Be aware that network speeds are the raw speeds not counting any overhead. You will never get the full 1 Gb / 125 MB while transferring data. With a good setup 900-950 Mb (112-118 MB) is possible on large files.

On top of that, most consumer level NASes cannot get anywhere near the above speeds. Some of the newer ones can, but if max possible speed is your goal then a PC as a NAS is the best option.

Ubtree
Posts: 34
Joined: Sun Jul 31, 2005 4:33 am
Location: United Kingdom

Re: Newbie question on speeds with NAS

Post by Ubtree » Tue Dec 04, 2012 6:38 am

Ubtree wrote:Hard drive speeds are often rated in mega bytes per second. Network speeds are always rated in mega or giga bits per second.
Of course! :oops:

Thank you very much for the reply - it's just what I needed to know.

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