Re: 6.0_BETA: Extreamly slow newfs_ext2fs on 60Gb USB stick

[Paul Fleischer <paul%xpg.dk@localhost>]

Hi Aleksey,

2012/3/1 Aleksey Cheusov <cheusov%tut.by@localhost>:
> For a number of reasons I decided to use ext2 filesystem on 60Gb memory
> stick.
[...]
> Unfortunately newfs_ext2fs works extreamly slowly
[...]
> To me this looks like kernel bug in USB subsystem. Any clue?

I might be completely off track here, but I think it is more likely
that you see the bad performance due to non-optimal partition and
block alignment on the memory used by the memory stick.
There is a good description of the problem here:
http://www.olpcnews.com/forum/index.php?topic=4993.0 and here:
https://wiki.linaro.org/WorkingGroups/Kernel/Projects/FlashCardSurvey.
I think the situation is the same for both SD-Cards and USB sticks.

So, you need to determine the erase block size of your memory stick
(or make a guess), and partitioning your stick accordingly, following
the rules from the olpcnews.com-link above:

"
Partitioning your card, you want your partitions to start at the
beginning of an erase block and to finish at the end of an erase
block. With 512b sectors and 4MB erase blocks you want to start at
sector: “N* 8192“ and to finish at sector “(N*8192)-1“, where N is a
natural number. The size of your partition will be
"(Nend-Nstart)*Eraze_block_size" in MB.
If flashbench says that you have a 2MB erase block, the numbers are
N*4096, if it is 1MB, N*2048, etc
"

I haven't tried this for USB sticks, but have seen good write
performance improvements on SDHC cards.

Cheers,
Paul