UBIFS size issue

[Altera_Forum]

Hello, 

 I am working with UBIFS,   When I am giving 55MiB of vol size, by following command ubimkvol /dev/ubi0 -N vol -s 55MiB  I could able to see only, 49 MiB of space when Kernel boot-up. Can any one please, give me some inputs regarding same. Thanks, Ashwin Rase

[Altera_Forum]

Hi, 

   --- Quote Start ---   When I am giving 55MiB of vol size, by following command ubimkvol /dev/ubi0 -N vol -s 55MiB I could able to see only, 49 MiB of space when Kernel boot-up.   --- Quote End ---    Can't you get the answer from here ?  http://www.linux-mtd.infradead.org/faq/ubifs.html#l_df_report  Kazu

[Altera_Forum]

Hello, 

 Thanks for reply,  I went through the links, it has mentioned about the free space i.e. "Use%" from below logs .  It also informs that how it varies. Following logs of mine is showing the same.  But I actually want to know that ,  when I create a volume by 55 MiB size and I get it as 49 MiB size after df -h, then  for what purpose 6 MiB (55MiB - 49MiB) is used ?  Why I could not able to see 55 MiB size, as allocated total space. ?  -- Following is the log -----  root@dhcppc7:~# df -h  Filesystem Size Used Available Use% Mounted on  ubi0:vol_1 49.2M 44.0M 5.2M 90% /  root@dhcppc7:~# sync  root@dhcppc7:~# df -h  Filesystem Size Used Available Use% Mounted on  ubi0:vol_1 49.2M 43.0M 6.2M 87% /  ------------------------------------------------------  Thank you,  Ashwin Rase.

[Altera_Forum]

Hi, 

   --- Quote Start ---   But I actually want to know that ,  when I create a volume by 55 MiB size and I get it as 49 MiB size after df -h, then  for what purpose 6 MiB (55MiB - 49MiB) is used ?  Why I could not able to see 55 MiB size, as allocated total space. ?   --- Quote End ---    UBIFS always reports conservative amount of free space, I think that the reason is written here.   http://www.linux-mtd.infradead.org/doc/ubifs.html#l_spaceacc  Kazu

[Altera_Forum]

Thanks Kazuyasu for your help