it's easy to use flashbench if you have a linux pc with sd and internet access. It can be ran on the pandora, but I used a Backtrack5 live dvd. Boot to the dvd then download the program to a directory, cd to the directory that has the program and with the sd card mounted (make sure it's not full of important data [backup to something first]) then do a flashbench -a <device> this will output some text that you can copy to a notepad. I would do it 2-3 times in a row and compair them all.
https://git.linaro.org/gitweb?p=people/arnd/flashbench.git;a=commitdiff;h=6aa1d51196783fb743a487e876645fb7ccbd76a0 Some info about flashbench output
http://bazaar.launchpad.net/~xnox/flashbench/master/files The files
Just going off mem with this instructions
If you had time you could format in all the diffrent formats and then time large filetransfers to see the speed diff. And if you lucky use the flash bench to see more detailed infomation about the block size.
In most cases you can just go off this
http://lists.laptop.org/pipermail/devel/2011-March/031505.html
Oh and I read were if the erase block was say 8megabytes and the max the ext4 filesystem block size is 4megabytes. Using 4megabytes will work great, the only time there is an issue is when you try to use a size Larger then the erase block.
h34r:
I looked at a lot of speed comparisons of ext4 vs ext4 without journal and when it came down to it, for me with journal was the way to go.
So if your drive is 64gigs or larger you are proably safe with saying you have a 4MB or larger page size, and the erase block size is = to or greater then this (withen a multipe of it 8,16,32,ect..). So....
Fdisk /dev/DEV
You get a menu
Command (m for help): m
hit u to change to sector view
hit d then the number to delete partion, need to delete them all if any
hit n for new partion
start at sector 8192 (Note this is 8MB start use 16384 for 16MBstart)*So 8MB will not be used... small price to pay for the alignment speed gain
then the end sector.... When you switched to u to see the total sectors you had a number. I took 8192 then added 4096 until I got as close to the end as possilbe then subtract -1 because it all starts at 0) Enter that
number. ex 18578334 total sectors / 4096 = 4535evenly so in this case 4535 x 4096 = 18575360-1 = 18575359 would be the end in this case.
hit l and find the number for linux
hit t and assign the number to the part
hit w to write
hit q to quit
Ok so now that the partion is alliend you have to format aligned as well...
enter partprobe (note this will remount sd with the new changes *actually write them)
mkfs.ext4 -b 4096 -g 32768 /dev/DEV
this command will format it to 4MB blocks with max group block size *note 5% of size is reserved for root access so the drive does not become to full "tune2fs -m 1 /dev/DEV" would change it to 1% I left it at 5 though.
So now it is formatted and alligend at the block, ready for testing. if you have a smaller card use the link to find the block size and do the math with the info above. Hope this helps!!
https://www.youtube.com/embed/videoseries?list=PLB68AF79BA3A34114
I wrote all this from mem so may need double check and revised
