time to mount static volume seems to be too long

[Artem Bityutskiy]

On Fri, 2011-04-08 at 16:59 +0300, Artem Bityutskiy wrote:
> Hello,
> 
> On Fri, 2011-04-08 at 14:48 +0200, Bastian.Ruppert at sewerin.de wrote:
> > [ubifs]
> > mode=ubi
> > image=/opt/rfsb/build/images/image.ubifs
> > vol_id=0
> > vol_size=46080KiB
> > vol_type=static
> > vol_name=rootfs
> > vol_flags=autoresize
> > 
> > I can mount the rootfs, but with this configuration the rootfs mount
> > time is about 8 Seconds for the image in a 71MB Partition.
> 
> IMHO, it makes little sense to use UBIFS on top of static volumes.
> Static volumes were really meant to store raw blob of data, where you
> want UBI to protect it with CRC for you.
> 
> UBIFS has its own CRC protection, so with static volume you get double
> CRC. Note, to force UBIFS checking data CRC on read you need to use
> "chk_data_crc" option, see here:
> 
> http://www.linux-mtd.infradead.org/doc/ubifs.html#L_checksumming
> 
> IOW, you do not need double-work.

BTW, if you appreciate the help from community and want to contribute,
it'd be nice if you wrote a short text to our FAQ:

"why a dynamic volume is faster to access than a static volume of the
same size?"

You can add it to this web page:
http://www.linux-mtd.infradead.org/faq/ubi.html

To do this, clone
http://git.infradead.org/mtd-www.git

edit faq/ubi.xml, type "make", make sure it compiles. Then open it with
your browser, check it looks good in html form, then send the patch.

Thanks! :-)

-- 
Best Regards,
Artem Bityutskiy (Артём Битюцкий)