Furyio
Posts: 23
Joined: Tue Jun 05, 2012 7:02 am
Location: Dublin,Ireland
Contact: Website

Pi write/download speeds, poor to SD card?

Tue Jun 05, 2012 7:13 am

Hi all,

I'm using my Pi primarily as a download manager. I used to have a laptop running

Sickbeard
Sabnzbd
Couchpotato
Headphones

And it was a brilliant setup, but with a 17inch laptop always on it was noisy, power hungry and cumbersome. It is the main reason I decided to get the Pi.

After a very easy setup, the Pi is running everything the same and I ran a test download of a set of photographs I host online, which comes in at roughly about 1GB.

I noticed that while the download speed was lvoely ( about 12mb/s) the pace at which it was "actually" downloading was abysmall. What I mean by this is that the progress bar in Sab was constantly freezing, and it would appear the issue might be the write speed to SD card?

The idea was the original download to go to a temp folder on the SD card, and then for a post proc script in sickbeard to move it to my NAS.

The only other alternative I have is

A) Temp folder on the NAS, but this will mean writing to the HD while also watching content etc. which is not a good solution
B) Mount an external hard drive and use that for the temp storage

Option B looks the best bet, the mounting process is very easy, but again no idea of write speeds.

Anyone with a similar setup have a good solution?

THanks,
Furyio
Raspberry Pi Debian Squeeze
IRC channels : #raspi.ie #d3.ie #att #airsofter.ie

tufty
Posts: 1456
Joined: Sun Sep 11, 2011 2:32 pm

Re: Pi write/download speeds, poor to SD card?

Tue Jun 05, 2012 10:43 am

Writes to (and reads from) the onboard SD card slot are extremely slow. You can expect to see sequential write performance of the order of around 4MB/s tops and that's with a "good" card. It's being looked into but you're probably better off using a mass-storage device hooked onto the USB bus instead.

Simon

Furyio
Posts: 23
Joined: Tue Jun 05, 2012 7:02 am
Location: Dublin,Ireland
Contact: Website

Re: Pi write/download speeds, poor to SD card?

Tue Jun 05, 2012 12:23 pm

Thanks,

That atleast confirms my assumption that it was read/write speeds.

I've a 320GB USB HD that I will mount later this evening and test on that. It is not a disaster, I've scheduled my downloads during the nightime so it can have that extra bit of time to download.

But at the rate the SD card was going, ugh.

I'll post back later with a little walkthrough of what I did :)
Raspberry Pi Debian Squeeze
IRC channels : #raspi.ie #d3.ie #att #airsofter.ie

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