Recommended SD Card Size


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by WereCatf » Mon Jan 30, 2012 4:53 am
Vindicator said:

SSD are fast but look at the capabilities of the main hardware the Raspi and after sharing the bus with all devices connected through the 9512 chip what advantage would a SSD serve except for maybe a wow factor.
Throw in the interrupts of that for polling amongst the devices and speed is of little to no matter.


Using an SSD on RPi would be an absolute overkill anyways. USB2 can in theory transfer 480Mbit/s or about 60MB/s, in reality it's closer to about 40MB/s. Ie. USB2 simply isn't fast enough for SSD usage.
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by laszlo » Mon Jan 30, 2012 5:55 am
The biggest benefit of SSD (and flash) is low latency.. I think if you can do it, it makes good sense to use a USB connected SSD over a rotating disk especially in this application.  While the benefit on a fast desktop may be minor, the benefit on something slow like this will be more visible.

The way they get them to have high sequential throughput on the more expensive ones (RevoDrive) is by having multiple controllers connected in parallel like a RAID striping.. but for this application a slow single controller one would be fine.
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by cnxsoft » Mon Jan 30, 2012 6:13 am
I have an image here (for the emulator) with Chrome (fluxbox windows manager) that is less than 1GB (I could probably strip it to 500 MB). I'll also need some extra space for cache and plugins, but a 2GB SD card would probably be sufficient.
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by steviewevie » Thu Feb 23, 2012 9:43 am
itimpi said:


I thought I remembered seeing posts at one time that suggested the RPi might have trouble with Class 10 SD cards! Does anyone have definitive update on this?


I'm curious about this too, particularly as I was just reading the Wiki, which says :


There are issues with most Class 10 SDHC cards, apparently due to a bug in the Broadcom bootloader


(from http://elinux.org/RPi_Verified.....eripherals )

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by MorgUK » Thu Feb 23, 2012 9:59 am
laszlo said:


Is there the possibility of using some type of fast SSD, through one of the other interfaces on the Pi maybe? I realize all these flash memory things are 'solid state' but I mean, whether it's artificially slowed down somehow or whatever else, the USB and SD/CF ones are really slow compared to the SATA or PCIe ones (even though there's a ton of inefficiency in the ones that pretend to be hard disks, in practice they're fast).  USB sticks get 5-10MB/sec writes whereas there are now SATA SSD packages that claim 500MB/sec read/write, and of course there are multi channel RAID type setups that work through the PCIe bus and do 2-3 times that.

Is the SD card expected to be 'better' for mass storage than the USB ports?  Would it be better to use one of these SanDisk Extreme SD cards that were mentioned, or maybe a more complicated contraption like USB port -> enclosure -> SATA SSD?  In practice what ends up being the bottleneck?


The SATA SSD's that achieve 500mb read/write are using SATA 3 connections. As others are said a USB disk drive a good option. Personally I will be getting a fast SD card and also use my USB 3.0 flash drive. Obviously it will only work in 2.0 "mode" but it's a lot faster than standard 2.0 drives. It gets 30mb read and 20mb write.
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by NewtonRev » Thu Feb 23, 2012 12:13 pm
Personally, I bought a Sandisk 4gb class 6 on Amazon. I think it is a good choice.
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by pietari-poika » Fri Feb 24, 2012 2:04 pm
Chromatix said:



The tl;dr version is that SanDisk are almost certainly the best brand to get at the moment - they have three main SD-card product lines which are all decent.  If SanDisk is not available, then either Transcend or Verbatim are tolerable substitutes - but avoid the Class 6 Transcend cards in capacities over 4GB.  Kingston are to be avoided like the plague.

HTH.


Hmm... I just ordered a Transcend 16GB Class 6 SD-card... should I cancel it and go for an A-data or SanDisk instead?
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by bbramble » Fri Feb 24, 2012 2:52 pm
No idea. Gone for a SanDisk Ultra class 6 8GB here.
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by alexjj » Fri Feb 24, 2012 3:35 pm
I ordered an 8GB Sandisk Extreme class 10 from play.com. Was £8.
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by riggsre » Fri Feb 24, 2012 3:54 pm
So, after reading this thread I was wondering; What is the recommended SD card size...

12+12 (this is getting hard)
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by laszlo » Fri Feb 24, 2012 3:58 pm
2GB is enough for the debian6 image available for download.  You can plug in a USB stick/drive and mount that for 'user' data, or you can get a larger than 2GB SD card and make a user partition on it or grow the existing partition + fs in the image.
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by jpxdude » Fri Feb 24, 2012 4:11 pm
I have to concur with Jessie in regards to reliability of certain brand cards.

It's surprising really to see such a positive response to Sandisk where I, and many others that I know have had mixed results with Sandisk SD cards.  I've had some reliable ones, but so many have also failed, become corrupted and unusable/unreadable as well.  Sandisks also have a tendency to be a lot slower than their rated speeds compared to other brands.

On the other hand I've had great luck with Kingston, and they've always been faster and more reliable for me than Sandisk.  As Jessie mentioned, a lot of the memory/SD cards are spat out generically from a generic location and then stamped with branding.  If I personally have a tip, then the key differentiator in reliability is location, and knowing the country and/or plant your memory came out of.

I know companies like Kingston produce SD cards from locations in quite a few countries.  I make sure I get my SD cards from a reputable seller, and that it is made in Japan.  I hear Taiwanese produced cards can be problematic.

Just my 2 pence...
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by NewtonRev » Fri Feb 24, 2012 4:58 pm
I received my sd card ( http://www.amazon.co.uk/SanDis.....038;sr=8-1 ) today.

result:

read 19.7 Mb/s

write  19.5 Mb/s

Now, I want to try it on the Rasb Pi @@ :(
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by S0litaire » Fri Feb 24, 2012 5:05 pm
I've just ordered 2 cards both from Amazon

1 x Integral SDHC Class 10 16GB £9.62

1 x SanDisk Micro 8Gb SD Card  + Adapter £6.49 (This is one of the new Ultra High Speed (USH) cards so not sure if it will be R-Pi friendly, so it's probably going to end up in my Smartphone!! lol ^_^
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