[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Keeping JFFS metadata separated from data.



On Sun, 24 Sep 2000, Bjorn Eriksson wrote:
>   Has anyone experimented with keeping the JFFS-metadata separated from the
> actual data, i.e on a completely different device? Given that this second
> device is 'fail-safe' would this simplify matters? Could the JFFS code
> itself and/or the data it writes be made more compact?
> 
>   I've got a new device here with 512KB SRAM w/ battery-backup (memory
> mapped) which I wan't to use to I want to implement an FS on NAND flash

Both the flash and your battery-backed SRAM are "failsafe" (or not,
depending on the definition). They just have different timings for
failsafeness :)

The filesystem would be faster if you for example have a lot of metadata
updates but almost no data updates, if you keep the metadata on a speedier
partition or device. But it won't be easier or more compact as far as I
can tell..

On the other hand if what you mean is that you can tolerate to corrupt
your filesystem when crashes occur that corrupt the SRAM (since the
corruption window is smaller than for flashes) then that's another case
but not one JFFS is designed to handle. In essence you'd be better of with
a completely different filesystem I guess.. 

-Bjorn