[Gluster-devel] max size limit on posix xlator PROOF of CONCEPT patch

Anand Avati avati at zresearch.com
Wed Jan 16 19:24:18 UTC 2008


Angel,
 Limiting filesystem size by tuning the params of statfs() is not possible.
statfs values are only meant to be a reference to the user, and not limiting
in any ways. So even if you get the tuning right, it will only be reflected
in 'df' output, and the filesystem will actually still be able to grow than
1GB in size.

 What really needs to be done is filtering write() calls and other calls
which create new inodes, This, in my opinion, is best done as a quota
translator, with your requirements being a global quota option.

avati

2008/1/17, Angel <clist at uah.es>:
>
> Hi, all
>
> This is my first proof of concept of limiting filsystem size on posix
> xlator.
> This far easy that implementing interception on filter module by now :-P
>
> test setup local posix xlator mounted on /home/sinosuke/mnt
> mounted directory is void.
>
> cmd line is:
>         glusterfs -N -L WARNING -l /dev/stdout -n trace-volume -f
> /etc/glusterfs/client_posix.vol /home/sinosuke/mnt
>
> RESULTS
>
> Normal posix xlator (as 1.3.8tla363)
> df -h
> S.ficheros          Size Used  Avail Uso% Montado en
> /dev/sda2             9,9G  4,6G  4,9G  49% /
> udev                  502M   88K  502M   1% /dev
> /dev/sda4              50G   21G   30G  42% /home
> glusterfs             50G   21G   30G  42%  /home/sinosuke/mnt
>
> proof of concept posix xlator mountes /home/sinosuke/mnt with option
> "max-size 1GB"
>
> sinosuke at sushiba:~/mnt> sinosuke at sushiba:~> df -h
> S.ficheros          Size Used  Avail Uso% Montado en
> /dev/sda2             9,9G  4,6G  4,9G  49% /
> udev                  502M   88K  502M   1% /dev
> /dev/sda4              50G   21G   30G  42% /home
> glusterfs             1,0G  -29G   30G   -  /home/sinosuke/mnt
>
>
> Other values ( used and vailable ) get insane values as they dont match
> current filesize reported :-(
>
>
> Comments welcome
>
>
> Kind regards, Angel
>
>
> --
> ------------------------------------------------
> Clist UAH
> ------------------------------------------------
>
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>
>


-- 
If I traveled to the end of the rainbow
As Dame Fortune did intend,
Murphy would be there to tell me
The pot's at the other end.



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