Any way to speed-up image read/write flash/sdcard

[bozden]

During development I use snapshot images of sdcard and usb flash disk (nand-sata-install'ed). Unfortunately, the size of common flash/sdcards do start at 16GB nowadays.

When I use Win32 Disk Imager, the backups are 2 * 16 GB. I can compress them on PC's disk but in and case writing them back to other sdcards/flash disks take ages. This is because it is a full image, although, say, something like 1 GB on each are used.

 

If there a way to make bootable images which includes only the used parts of the sdcard/flash and be able to write them back?

 

[Igor]

Possible. Take a look at this part of the script:

https://github.com/igorpecovnik/lib/blob/second/common.sh#L257-L300

[tkaiser]

6 hours ago, bozden said:

If there a way to make bootable images which includes only the used parts of the sdcard/flash and be able to write them back?

The Etcher guys are looking into exactly that including re-partitioning (and they always do a verify, please folks stop using stupid tools like Win32 Disk Imager that blindly trust in hardware). But it seems the necessary bits are postponed since they focus on different major tasks now.

 

My approach on this is an automated cloning routine for SD cards but I prevent Armbian's auto resize to use the full capacity in the first place (see here). This leads to eg. 3.6GB used for the rootfs and so later it's easy to do something like this:

ddrescue -s 3957325824 /dev/disk2 SD-card.img SD-card.log

(this is on macOS, on Linux you would've to use something like /dev/sdX instead -- see basics). The resulting image can then be written on any SD card with 4GB or more and will also use just 3.6GB there (which will reduce burning time too)

[bozden]

@Igor & @Thomas, thank you / danke for heads up...

 

I'm afraid I need some time to digest those scripts.

 

As a side note: I tried Etcher (still beta) on Win10 x64 a while ago but it did not work at all... Perhaps I need to try once more...