[Yaffs] mount time variable

Hi,
I have searched into the old posts and googling but I have not found any answer.
I use an ARM board with NAND flash 1GB.
I'm trying to use yaffs.
I have done some tests and it seems much better that JFFS2 (regarding
mount time).

I have only a doubt.

My system mount automatically yaffs2 file system at startup.

If I write into yaffs2 partition and I use "umount" or "sync" before
turn off the power, the successive mount command is very fast (about
0.1sec)
If I write into yaffs2 partition and I don't use "umount" or "sync"
before turn off the power, the successive mount command is very slow
(about 13sec)

A solution could be to have a background task :
while [ 1 ]; do sync; sleep 1; done
but obviously it is not good.

I have not found any configuration option that solve this problem.

Have you got some suggestion ?

Thanks in advance.

Paolo