[Arm-netbook] Fwd: Notification from Dropbox

[Gordan Bobic]

Alejandro Mery wrote:
> On Thu, Apr 19, 2012 at 17:06, Gordan Bobic <gordan at bobich.net> wrote:
>> Weird. How big is the actual file? I would expect a reasonably
>> minimalistic rootfs to compress down to < 150MB, which I wouldn't expect
>> to get noticed.
> 
> it's a dd image of a 4GB SD card

That doesn't mean it should be significantly bigger than the tar ball if 
it was made cleanly. If you have a recent e2fsprogs and kernel you 
should get discard support on MMC, so a mkfs should blank all the unused 
blocks (i.e. those should all compress to not far from 0 bytes).

 From there on if you only did a minimal clean install (or extracted a 
rootfs tar ball), the compressed dd image shouldn't be _much_ bigger 
than a tar ball of the rootfs.

Having said that, is there a good reason why a tar ball wouldn't be more 
useful anyway? It would let people format up the SD card in a way that 
may be more suitable to that particular card (e.g. different erase block 
sizes, etc.). SD cards are sufficiently slow that every small thing like 
that helps to make the performance bearable.

Gordan