Mounting Filesystem over existing directory

[Didier Kryn]

     Hi Sameer.

     There is a very simple alternative in case you only need to update 
a small number of well known files: softlink them to some r/w location, 
like /var/run or /lib/init/rw, which you mount on tmpfs. The second of 
these locations is created early in newer Debian versions and used by 
some packages like resolvconf.

     Didier

Le 31/05/2012 08:04, Bartos-Elekes Zsolt a écrit :
> Michael Conrad wrote:
>
>> Unionfs has one problem though: the only way to get correct behavior 
>> is to merge path A and B onto mountpoint C.  (C can't be the same as 
>> A or B).
>
> Perhaps this is valid only for older versions of unionfs. I am using 
> unionfs mounted on /var that is composed of a tmpfs mounted on 
> /mnt/tmpfs, and the original /var that is on the flash (containing 
> only a few important files and directories that must be preserved 
> across reboots, like /var/lib/dpkg).
>
> $ mount | grep "unionfs"
> unionfs on /var type unionfs (rw,relatime,dirs=/mnt/tmpfs=rw:/var=rw)
>