APM

[Chuck Swiger]

Hi--

On Nov 13, 2009, at 3:54 PM, David Allen wrote:
>> I'd consider adding something to /etc/rc.d/mountcritlocal (which
>> normally mounts the local filesystems) to setup a RAMdisk on /var and
>> then do "rsync -a /var_template /var" (or use a dump/restore or tar
>> pipeline).
>
> At the risk of sounding obtuse while asking for more help, I can work
> out the rsync or dump part, but the rest I don't  get. The
> mountcritremote essentially just does a mount -a -t ..., yes?  To
> insert a few mdmfs commands followed by rsync commands, for example,
> would require re-writing most the script.  Is there  a better place to
> this?

Quite possibly.  I used NetBSD for a flash-based Soerkris boxes a  
while back, rather than NanoBSD.  It looks like reading /etc/ 
rc.initdiskless might be informative.

> The reason I ask is that some time ago I had a look at nanobsd which
> is designed to run on RO flash media.  The /var and /tmp directories
> are created as memory devices that supposedly get re-populated from a
> /cfg directory at boot.

Right...

> The /usr/src/tools/tools/nanobsd/nanobsd.sh setup script has a
> function named setup_nanobsd_etc.  Essentially, it writes out an
> /etc/fstab file and does a 'touch /etc/diskless'.  Unless there's
> magic that happens behind the scenes with that /etc/diskless file, I
> don't see how anything gets re-populated.

The existence of /etc/diskless means /etc/rc runs /etc/rc.initdiskless:

% grep diskless /etc/rc
dlv=`/sbin/sysctl -n vfs.nfs.diskless_valid 2> /dev/null`
if [ ${dlv:=0} -ne 0 -o -f /etc/diskless ]; then
	sh /etc/rc.initdiskless
# Run these after determining whether we are booting diskless in order
# to minimize the number of files that are needed on a diskless system,

Regards,
-- 
-Chuck