[Discuss] Android backups

[richard.pieri at gmail.com (Richard Pieri)]

Edward Ned Harvey (blu) wrote:
> But the idea that you can't fully backup without shutting down is
> incorrect.  For at least android, windows, mac, and linux.  I don't
> know if there's such a thing for ios. 

Well... maybe. There are problems with trying to take a full snapshot of
Android while it's running.

A big one is that /data and /cache are highly dynamic file systems.
/data is where all your applications, saved data and configurations are
stored. /cache is the Dalvik cache. If anything is running -- and
something is ALWAYS running when Android is operational -- then the
contents of these two directories can change while the backup is being
made. Attempts to restore these directories can lead to corrupted data
being restored. It's the same problem that dump/restore have on live
file systems. Android doesn't use a LVM. The only way to get a reliable,
complete backup of these file systems is to do it from the recovery and
this requires a restart.

Another is that you can't do a full restore on a running system. /boot
and /system are typically mounted read only. These are the actual Linux
kernel operating system directories. While you can get around the read
only mount with ADB or root shells on the device, restoring them is
exactly like trying to restore / and /usr on a live Unix-like system --
because it IS a live Unix-like system.

-- 
Rich P.