Dear J.R.,

On Tuesday 06 October 2009 15:23:29 [email protected] wrote:
> As you might know, aufs1 doesn't support linux-2.6.28 and later.
> So I guess debian people modified the aufs1 source files.

Yes, they patched it accordingly.
 
> > > For
> > > instance aufs XINO files are such files, and the size of these files
> > > are listed in /sys/fs/aufs/si_*/xino. They may be the one you are
> > > looking for. (but I am not sure)
> >
> > Possibly. However, I am unable to interpret these:
> >
> > [r...@gibraltar-500 ~]# cat /sys/fs/aufs/si_7*/xino
> > 8x4096 4096
> > 0: 1, 696x4096 3320260
> > 1: 1, 48x4096 43540
> > 8x4096 4096
> > 0: 1, 6544x4096 3358868
> > 1: 1, 56x4096 152592
> 
> According to your /proc/mounts, you have two aufs mounts, /etc and /var.
Correct.

> /sys/fs/aufs/si_76a81819/xino shows the information about XINO files for
> /etc, and si_772cd879/xino is for /var.
Ah, ok - the parameters in /proc/mounts correlate with the sysfs files.
 
> For /var, there are one XIB(inode bitmap) and two XINO files.
> Your /sys/fs/aufs/si_772cd879/xino shows that,
> - XIB consumes 8 blocks in /system/ramdisks/var,
> - one of XINO files consumes 6544 blocks,
> -  and the other consumes 56 blocks.
Why are there two XINO files - for the two lower branches, I assume?

> Since the block size of /system/ramdisks/var is 4k, all of your XINO
> files for /var consumes (8+6544+56) x 4k = about 2.7MB.
Ok, but that still leaves me about 1MB short. "du -sh" shows 7.3MB, while "df 
-h" shows 11M used. 7.3+2.7 is roughly 10MB. Is there any indication where 
that extra 1MB is left?
 
> I hope this is the answer of your question.
> See the aufs manual for detail.
<snip>
Thanks for the pointer. With the details you gave above, I was able to 
interpret the manual page a little better. 

Could these XINO files be responsible for consuming up to 15MB when overlaying 
a read-only /etc tree with a tmpfs, when there are only less than 4000 files in 
the first branch and roughly less than 100 in the tmpfs branch?

The manual page mentions that "noxino" should not be used for the general 
case. However, when it is highly important to minimize disk space usage (that 
is, memory usage when tmpfs is used), would it be an option to use "noxino" 
for /etc and /var? In your experience, which applications break with such a 
setting?

PS: I have now updated to aufs2-30 standalone for a test system. However, I 
assume the XINO file handling will not have changed and this would therefore 
not solve my current problem, correct?

best regards,
Rene

-- 
-------------------------------------------------
Gibraltar firewall       http://www.gibraltar.at/

Attachment: signature.asc
Description: This is a digitally signed message part.

------------------------------------------------------------------------------
Come build with us! The BlackBerry&reg; Developer Conference in SF, CA
is the only developer event you need to attend this year. Jumpstart your
developing skills, take BlackBerry mobile applications to market and stay 
ahead of the curve. Join us from November 9&#45;12, 2009. Register now&#33;
http://p.sf.net/sfu/devconf

Reply via email to