folder lost+found missing?

[Paul F. Almquist]

On Saturday 05 March 2005 11:36, HaJo Schatz wrote:
> On Fri, 2005-03-04 at 12:57 -0600, Hongwei Li wrote:
> > Hi,
> >
> > The folder lost+found in the partition /tmp of my fc3 system is missing.
> > All other partitions have it.  What is the usage of lost+found folder? 
> > Do I need to create it for /tmp?  If yes, just run mkdir ...?  Do I need
> > to do anything special for it?
>

fsck will create it when doing a check if it is not there or you could create 
it with mkdir. however,  on my fc3 system /lost+found is 16384 bytes while a 
newly created directory made with mkdir is 4096 bytes.  mkdir(1) and mkdir(2) 
list no option to specify the size for a new directory.  The extra space may 
be to eliminate expanding the directory during recovery by fsck.


> lost+found is a dir which exists on each partition. It's used to store
> recovered data in case you had a fs-inconsistency and fsck tried to
> repair it but was left with some chunks of data which it couldn't "sort
> in" -- these chunks go to lost+found for you to recover manually later.
>
> /tmp is per definition a directory which holds temporary data which does
> not have to survive a reboot. Hence a recovery of that dir/partition
> during reboot doesn't really make sense -- the data to be recovered is
> uselelss anyhow. 

that really depends on how the user or programs use /tmp rather that the 
definition of /tmp.  Some data may be temporary but still valuable and worth 
recovering.  It is probably better to recover it and not need it than not 
recover it and wish you had.

> AFAIR /tmp is actually cleaned automatically at every 
> reboot.
All I find for boot time cleaning is the following in /etc/rc.d/rc.sysinit:
# Clean up various /tmp bits
rm -f /tmp/.X*-lock /tmp/.lock.* /tmp/.gdm_socket /tmp/.s.PGSQL.*
rm -rf /tmp/.X*-unix /tmp/.ICE-unix /tmp/.font-unix /tmp/hsperfdata_* \
       /tmp/kde-* /tmp/ksocket-* /tmp/mc-* /tmp/mcop-* /tmp/orbit-*  \
       /tmp/scrollkeeper-*  /tmp/ssh-*

a daily cron job does a cleaning of /tmp.  see /etc/cron.daily/tmpwatch and 
tmpwatch(8)

> It may very well be a bug of the cleaning routine to also delete lost
> +found in the progress during reboot. Whether this is is a serious one
> however is not so clear to me -- you're never supposed to recover
> anything on this partition anyhow...

Do you actually have /tmp in a separate partition? I do not, so there is no 
lost+found directory in it.

paul

-- 
Paul F. Almquist
paul at almquist.name
Eau Claire, WI  USA