Re: btrfs raid1 filesystem on sdcard corrupted

[Goffredo Baroncelli <kreijack@inwind.it>]

Hi Robert,

On 2016-02-25 20:18, Hegner Robert wrote:
[...]
> So, in your experience 1) Which are the SDcards we can trust in?
> (brand? model?)

For this kind of use you should look to an "industrial grade" SD cards. But these are quite expensive (we are talking about 50€ for 4GB....). Our supplier suggested us the ATP sd cards [*].

I tested a NON industrial grade sdcard with simulated power failure; my test showed that this card fails quite early (about hundreds of cycles).
I have to point out that "industrial grade" is a generic definition. Unfortunately I was unable to find a more detailed spec.

> 2) What would be a better way (with or without the use of btrfs) to
> make an embedded system more robust against power failures and
> flash-memory-wearing?

If it is possible to avoid don't write on the storage Don't log. Leave the filesystem "read only" and switch to read/write only when you have to write; after the write re-switch the filesystem RO. This cannot prevent the damage of the card, but could reduce the likelihood of the damage.

I never tested the internal flash of these boards. May be that this flash is more reliable...

BR
G.Baroncelli

[*] "http://www.digikey.com/product-search/en?mpart=AF8GUDI-OEM&vendor=1282"

-- 
gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it>
Key fingerprint BBF5 1610 0B64 DAC6 5F7D  17B2 0EDA 9B37 8B82 E0B5