Should I buy an external device to store data on

Question

I'm planning to use my pie 24/7, but SD cards are not made for this. Because of that I want to reduce the read and write jobs on the card so it will last longer. There are several options to do this;

I could use an external hard drive to run real time programs on;
I could use an USB stick to run real time programs on.

I prefer an USB stick because it doesn't make noise, but it also uses flash memory. So is it wise to buy an USB stick for real time jobs? Because then I could store everything on the USB stick, except the OS of course.

I have a 2 ampere power supply, so in my case you don't need to worry about the power supply. I have an model B 256 MB version. — Laurence, Nov 15 '12 at 12:59
You should also look at How can I extend the life of my SD card?. Large SD cards are so cheap now that overprovisioning can easily give you the longevity you need. — Mark Booth, Nov 15 '12 at 14:15
@XTL - It's not really an answer to the question asked, it's an answer to a slightly different question that I think is still relevant, hence leaving it as a comment but linking to my answer to the other question. — Mark Booth, Nov 16 '12 at 13:58

Laurence · Accepted Answer · 2012-11-15T14:03:27.867

I did some calculations:

An USB with SLC NAND Flash can do maximum 100.000 write cycles. On an USB with 8GB with 10 MB/s write speed will that be:

(My math skills or not very good, I know for sure you can do this on an easier way)

((8192 / 10 )) * 100.000) / (365.242 * 3600 * 24) = 2.595945012206012 years.

So, when you write on your USB with 10 MB/s for 2,6 years it will be broken. Its true that it will be broken earlier. but when you have a good controller it will last very long. So yes, an USB with SLC NAND flash is a good option.

You also have SD cards on SLC NAND flash, but I don't know the technical details about the controller in the Raspberry pi, besides that. In my country an USB stick is cheaper then a SD card. So I bought a small SD card and an USB stick.

There is one downside, an USB stick needs power. USB can max consume 0.5 ampere. Model A of the PI has a limited USB power output, and not every power supply’s can handle that much amperes. So you need to check this before you buy an USB stuck for your PI.

Source: “SLC NAND flash is typically rated at about 100k cycles (Samsung OneNAND KFW4G16Q2M) ” on the page: http://en.wikipedia.org/wiki/Flash_memory

Should I buy an external device to store data on

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