Saving objects

On shutdown, PPS always saves any modified objects in a persistent filesystem. You can also force PPS to save an object at any time by calling fsync() on the object.

When PPS saves its data in a persistent filesystem, it saves each object in its own file, in a directory hierarchy that reproduces the hierarchy of the PPS object tree. For example, with a default configuration, the PPS object /pps/example/object1 is stored at /var/pps/example/object1.

The default location for the PPS directory is /var/pps. You can use the PPS -p option to change this location.

Note:

It's possible to edit the persistent version of the PPS files. If security is important to your system, you should have PPS save its data in an encrypted filesystem.
You can set object and attribute qualifiers to have PPS not save specific objects or attributes.

Changing the directory for persistent storage

The root PPS object tree (/pps by default) may look something like this:

# pwd
/pps
# ls -1F
accounts/
applications/
qnx/
qnxcar/
servicedata/
services/
system/
#

PPS populates its root object tree from the persistence tree (/var/pps by default), where the objects and attributes that you want to persist are stored.

To specify a different directory for persistent storage:

Create your own persistence directory (e.g., mkdir /myobjects).
Start the PPS service from a different mountpoint (e.g., /fs/pps) and specify your new persistence directory:
pps -m /fs/pps -p /myobjects

Note: You may want to run PPS with the -t option, which configures PPS to write to persistent storage at the interval you specify. Without the -t, you won't see any changes in your persistence directory until PPS exits. For more information, see Running PPS.