[Voyage-linux] External USB drive : about writable folders, usb module, and using either ramdrive or usb drive

[Nicolas Pillot]

Hello,

Now that my system is up and running (from the CF card, no drive), i
want get some storage. But i'm thinking : why not get the CF card to
host he root filesystem in read-only mode, and use a couple of
partitions on the external drive to host the ones which are
"writable", so i don't damage my CF card with continuous writing.

Then came the following question :

Q1 : which "folders" are in fact writable in a standard directory tree ?
- /VAR for the logs, at least
- /TMP obviously
- Are there any others ? (appart from upgrading the system itself, ofc)

Q2 : Are the mounted directories processed all at the same time ? ie
if i set an entry in fstab telling to mount /dev/sdaX (which is the
usb drive) to VAR/TMP, will the usb modules already be loaded when the
mountoperation is performed on startup ?

Q3 : afaik, mounting a drive into a non-empty directory "hides/erases"
the existing entries in the VFS, is it true ?
That could be a good point, because as i understand it :
- if the usb drive is connected, the ALIX will use the partitions from
the USB drive for VAR/TMP
- if the usb drive is not connected, the ALIX would use the ro/rw
ramdrive from Voyage
Did i get that part correctly ?

Thanks in advance

-- 
Nicolas Pillot (nicolas.pillot at gmail.com)