how to properly calculate max-leb-cnt and vol_size for ubifs

how to properly calculate max-leb-cnt and vol_size for ubifs

[twebb]

I'm using ubifs for the first time and am confused about how to
calculate two parameters:

"max-leb-cnt" for mkfs.ubifs
"vol_size" for ubinize cfg file

How should "max-leb-cnt" be calculated?  In the examples, how is "-c
2047" determined?  Should the max-leb-cnt calculation somehow include
the overhead calculated per the ubifs documentation page?  Should the
reserved PEBs (1% default for NAND flash) be somehow taken into
account?

How should "vol_size" be calculated?  Is it simply max-leb-cnt *
LEB_size?  Should overhead somehow be included in this calculation
also?

Thanks for the help,
twebb

Re: how to properly calculate max-leb-cnt and vol_size for ubifs

[Adrian Hunter]

twebb wrote:
> I'm using ubifs for the first time and am confused about how to
> calculate two parameters:
> 
> "max-leb-cnt" for mkfs.ubifs
> "vol_size" for ubinize cfg file
> 
> How should "max-leb-cnt" be calculated?  In the examples, how is "-c
> 2047" determined?  Should the max-leb-cnt calculation somehow include
> the overhead calculated per the ubifs documentation page?  Should the
> reserved PEBs (1% default for NAND flash) be somehow taken into
> account?
> 
> How should "vol_size" be calculated?  Is it simply max-leb-cnt *
> LEB_size?  Should overhead somehow be included in this calculation
> also?

Have you read:

http://linux-mtd.infradead.org/faq/ubifs.html#L_max_leb_cnt

http://linux-mtd.infradead.org/faq/ubi.html#L_ubi_mkimg

http://linux-mtd.infradead.org/doc/ubi.html#L_autoresize

Re: how to properly calculate max-leb-cnt and vol_size for ubifs

[twebb]

>>
>> I'm using ubifs for the first time and am confused about how to
>> calculate two parameters:
>>
>> "max-leb-cnt" for mkfs.ubifs
>> "vol_size" for ubinize cfg file
>>
>> How should "max-leb-cnt" be calculated?  In the examples, how is "-c
>> 2047" determined?  Should the max-leb-cnt calculation somehow include
>> the overhead calculated per the ubifs documentation page?  Should the
>> reserved PEBs (1% default for NAND flash) be somehow taken into
>> account?
>>
>> How should "vol_size" be calculated?  Is it simply max-leb-cnt *
>> LEB_size?  Should overhead somehow be included in this calculation
>> also?
>
> Have you read:
>
> http://linux-mtd.infradead.org/faq/ubifs.html#L_max_leb_cnt
>
> http://linux-mtd.infradead.org/faq/ubi.html#L_ubi_mkimg
>
> http://linux-mtd.infradead.org/doc/ubi.html#L_autoresize
>
>

I have, and I'm still pretty confused.  I just posted some additional
questions I'm hoping perhaps you or someone else may be able to help
with.

Thanks,
twebb