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I want to use a Netgear ReadyNAS 2100 to store and stream H264/MPEG4 videos. Each video differs in size, but ranges from a few hundred MB to a few GB. On average, each video will be 500MB in size and the duration will be about 45 minutes long.

There are 10 users in the office and most will be streaming the videos at the same time. They're using an Adobe AIR application and Wowza/RTMP to stream the video. Most users will happily play a single video from start to finish but others will be seeking throughout the video.

Can anyone suggest what spindal speed hard drives I should be using for this operation?

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closed as too localized by voretaq7, MadHatter, Ward, Iain, MDMarra Nov 21 '11 at 18:52

This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center. If this question can be reworded to fit the rules in the help center, please edit the question.

Insufficient Information: You remembered to tell us the codec you're using (which is good because that's important) but neglected to tell us How big the videos are, if people will be requesting one video over and over (so it can sit in cache if it's small enough) or lots of random videos (which means lots of random disk I/O), etc. -- We need to know a lot more about your environment to be helpful, and once this question is that tightly tailored is might not be useful for other people. All that said, faster disk is better. In your situation I'd spring for at least 10K drives. –  voretaq7 Oct 31 '11 at 16:05
Thanks, I've re-posted a better question as per your suggestion. –  Reado Oct 31 '11 at 16:28

2 Answers 2

For sequential reads (like video streaming), the most important factors are the number of spindles and the number of bottlenecks in the data path. Each drive adds its performance (in terms of MB/s) to the aggregate performance of the raid. The speed of each drive will be a factor, but usually even just a few drives is enough to saturate some other bottleneck in the data path.

5400 and 7200 RPM drives (and even 10 or 15k RPM) all perform pretty close. The first three pages of these benchmarks from tom's hardware will demonstrate that the factors other than spindle speed are actually more critical from a throughput standpoint.

Firstly, the disk controller has to be able to read from a raid 5 as fast as your clients can request data. This means typically it needs to have a decent amount of internal and external bandwidth, with as few shared resources as possible. Secondly, the connection between the NAS and the network the clients will be using to request data needs to be thick enough to handle a bunch of concurrent streaming. Third, that same network can't have under-powered ASICs powering the ethernet ports, leading to an "oversubscription" environment where any port can burst to 1Gb/s, but they can't all do it at the same time.

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Doing an estimation with the given figures, a single requester will need 500 MB / 45 minutes / 60 seconds/minute = 185 KB/s of throughput. Rounding up to 300 KB/s and considering that reads are likely to happen in rather large blocks due to client buffers, you should be fine with every desktop-grade drive even for 10 simultaneous streams.

The rotational speed is mainly a matter of concern if you have significantly random load with small request sizes - like database or SAN operations. Your scenario imposes a rather low semi-linear load on the disk so you should be able to go with nearly everything that's available today.

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Thanks for your reply. If I wanted to host SBS data such as files, documents and SQL databases on the drive in addition to storing/streaming video, would I then need to consider going for faster drives? –  Reado Nov 1 '11 at 8:22
The ReadyNAS is a 4-drive-enclosure with RAID capabilities. Depending on how you configure it, it would give different performance results. But for any meaningful load, especially if you mix applications and SQL databases on the same storage set the answer probably would be "yes". –  the-wabbit Nov 1 '11 at 10:13

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