Hi
How reliable and durable are SD Cards and Flash memory. Im thinking of getting an netbook, one of those little EeePC things but the earlier models have limited internal Flash memory.
So, extra storage would be in the shape of Flash drives or SD cards.
How reliable are they for storing stuff? I read somewhere about the 100,000 rewrite limitation, but how true is this.
Ive got a USB thumb drive that I have had for about 6 years and it is still going strong. It has outlasted some of my newer ones. It used to house my website files so was used on a daily basis, written to dozens of times at once.
Simon
On 05/02/11 22:38, Simon Royal wrote:
Hi
How reliable and durable are SD Cards and Flash memory. Im thinking of getting an netbook, one of those little EeePC things but the earlier models have limited internal Flash memory.
So, extra storage would be in the shape of Flash drives or SD cards.
How reliable are they for storing stuff? I read somewhere about the 100,000 rewrite limitation, but how true is this.
I think modern and reputable make SD cards/flash memory are now durable to the point that unless you are using them in heavy write scenarios (swap or log files) then the lifetime will exceed the usefulness as technology advances.
I have had a few usb flash drives die in my time but most of them have been due to rough handling/water damage/connector damage. I can't remember having an SD/CF card fail on me.
Also bear in mind that these figures are talking about writes to a specific block. file allocation,fragmentation and wear levelling in the flash controller all have an effect on this so the real figure will be better.
If you are really concerned then making sure you mount with noatime and using a non journalling FS will help prolong life..and improve speed as with flash memory writes are usually slower than reads.
Simon Royal wrote:
Hi
How reliable and durable are SD Cards and Flash memory. Im thinking of getting an netbook, one of those little EeePC things but the earlier models have limited internal Flash memory.
Never had any fail. My oldest one is 64 MB, and I had that when it was state of the art.
If you do get an Eee and it has Xandros on it, I'd advise you to install a proper distro on it. I've had xPUD and Crunchbang recommended for the purpose. With Xan-dross on the Eee (or at least, my Eee) you can't use the USB for anything else if you have an internet dongle plugged in.
If you then want to use anything else in the USB port(s) you have to remove the dongle and reboot first.
The dongle won't work if you have a SD card in the slot either.
Other distros installed on the Eee don't suffer from this failing, I'm told.
I believe you can get at least 32 GB SD cards - but at a price. (8 GB is currently around £23, but I am told that it's cheaper on the continent.)
So, extra storage would be in the shape of Flash drives or SD cards.
How reliable are they for storing stuff? I read somewhere about the 100,000 rewrite limitation, but how true is this.
That's hardly a limitation. Don't forget, your Eee will have similar 'limitations'...
On Sun, Feb 06, 2011 at 01:23:05AM +0000, Anthony Anson wrote:
I believe you can get at least 32 GB SD cards - but at a price. (8 GB is currently around £23, but I am told that it's cheaper on the continent.)
Wow, you must come from the past in a time machine! :) I got a 16GB micro-SD last month for £18 and a 16GB SD for £16. On top of that I paid a premium to make sure I got a card from a reliable retailer (so nothing fake) and getting fast cards. 8GB is around £8-£10 at the moment, it now means that when I fill an SD card up in a camera that all I do is buy a new card and put the old one in the fire safe.
Anyhow, as for the 100,000 writes thing. That is 100,000 writes per block (and is quite an old metric from ye olde days of flash). How often will you actually write to the card? I mean, assuming that you do actually do 100 writes a day to the *entire* card that's still nearly 3 years of life at which point you can throw it away and buy a new one that will have 8x the capacity of the same price.....
Adam
Adam Bower wrote:
On Sun, Feb 06, 2011 at 01:23:05AM +0000, Anthony Anson wrote:
I believe you can get at least 32 GB SD cards - but at a price. (8 GB is currently around £23, but I am told that it's cheaper on the continent.)
Wow, you must come from the past in a time machine! :) I got a 16GB micro-SD last month for £18 and a 16GB SD for £16.
Where?
On top of that I paid a premium to make sure I got a card from a reliable retailer (so nothing fake) and getting fast cards. 8GB is around £8-£10 at the moment,
Where?
it now means that when I fill an SD card up in a camera that all I do is buy a new card and put the old one in the fire safe.
It's this 'reliable retailer' thang - The Swedes (Chapelfield Mall) charge £23 for 8 giggle, as do various camera shops and allied businesses.
I *KNOW* you can et them at sensible prices (a correspondent in Germany does), but apart from buying online *I* can't find anyone - in Norwich, at least. Online's OK unless you want one *now*.
On Sun, Feb 06, 2011 at 11:58:18AM +0000, Anthony Anson wrote:
Adam Bower wrote:
Wow, you must come from the past in a time machine! :) I got a 16GB micro-SD last month for £18 and a 16GB SD for £16.
Where?
www.7dayshop.com
On top of that I paid a premium to make sure I got a card from a reliable retailer (so nothing fake) and getting fast cards. 8GB is around £8-£10 at the moment,
Where?
www.amazon.co.uk (order fulfilled by indigo starfish)
I *KNOW* you can et them at sensible prices (a correspondent in Germany does), but apart from buying online *I* can't find anyone - in Norwich, at least. Online's OK unless you want one *now*.
Sainsbury's were selling 8GB SD cards in their Pound Lane store the other day for £12.
Adam
Adam Bower wrote:
www.7dayshop.com
www.amazon.co.uk (order fulfilled by indigo starfish)
Sainsbury's were selling 8GB SD cards in their Pound Lane store the other day for £12.
Thanks.
(They'll have to wait for a week or two now till I get the recently blown-off bargeboards and some tiles replaced...)
Flippin' wind...
On 14/02/11 22:38, Simon Royal wrote:
Ive been reading about the limited writes on SSD, with conflicting info.
Does anyone have a clear info on this. Do they have limited write capabilities? Is this within a normal users/machines lifespan? What happens when it reaches it write limit.
Short answer is that yes they do have a limited (write) life although unless you do something intensive that is always going to write to the same blocks it is unlikely you will hit it in normal lifespan given reasonable quality and modern flash ram.
There are tricks to reduce write such as use a non-journalised file system like ext2 instead of ext3/4 and do not use a swap partition.
Yes that helps and everything on (cheaper) flash that avoids writes will also give you a speed boost as writes generally take more time (and power) than reads.
So in addition to that you might want to mount with the noatime option unless you really need access timestamps (unlikely)
Maybe you could also mount /var/log and possibly /var/tmp as tmpfs if it is the sort of machine where you aren't too worried about keeping log files between reboots.
I would recommend either not using a swap file (assuming you have lots of ram and don't care about suspend to disk) or if you do maybe look at the vm.swappiness kernel parameter to reduce how much it is used.
Finally I have also seen boosts by changing from the default cfq (on most distro's) to the noop I/O scheduler in much the same way as I have seen on VM's but YMMV
I really hope someone doesn't repost this question under a different Subject after I have taken all this effort to reply once already...that would be annoying.
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Adam Bower -
Anthony Anson -
Simon Royal -
Wayne Stallwood