I've been playing with NFS booting, and it's really easy to setup with a FreeNAS server (8.3.0-RELEASE).
Performance is very good, even booting is only marginally slower than SD card (about 35 seconds with class 10 SD card, 40 seconds over NFS with ancient pre-Class system SD card).
Just create the NFS share with "All Directories" ticked, "Maproot User == root" and "Maproot Group == wheel". Once created, you should have an entry in /etc/exports similar to the following:
Then within the share, create a "System" and "Storage" folder.
Within the System folder, copy in the OpenELEC SYSTEM file. That's all that needs to be in there. However, if you have multiple clients it might make sense to create individual client folders within the System folder so that each client can auto-update at their own pace (clients running older firmware may break if they pick up a newer SYSTEM file). So with multiple clients, create rpi#1, rpi#2 folders and within each of those folders copy in the SYSTEM file.
Within the Storage folder, if you have multiple Pi's you should create further sub-dirs for each client, eg. rpi#1, rpi#2 etc. Leave the folder empty so that it will be initialised by the R-Pi - later on you can create a backup and duplicate it for new clients (eg. restore a busted client back to "known good state" etc.).
On the Pi SD card, create a single FAT partition with the following files from the OpenELEC package:
Note that you no longer require the SYSTEM file on the SD card, meaning the SD card can be as small as 8MB (though 16MB would be a more sensible minimum). Performance of the SD card is also now largely irrelevant, as it's only required during boot (and when updating the system software - a rare occurrence under normal circumstances).
Set config.txt to your own requirements (overclocked, gpu mem etc. etc.).
For cmdline.txt, specify the following to enable NFS booting (make sure it's all on one line):
where 192.168.0.200 is my FreeNAS server - change to match that of your own server, also the NFS mount point.
Then boot your Pi, as that's all there is to it.
Unfortunately (as of OpenELEC Beta 6), auto-update is not currently working correctly with NFS boot (issue #1653) but other than that, NFS booting is a pretty good solution as it makes the system a lot more resilient to SD card corruption (since there are now no SD card writes, except when updating system software - disable auto-updates to prevent ALL SD card writes), boot performance is still very good, you can use any old SD card (even the smallest, slowest you have lying around - no need for uber-fast or large capacities etc.), and it simplifies backups and new client setup (just duplicate the Storage folder of an existing client).
Conceivably, a simple cron job running on the FreeNAS server could be used to rsync the Thumbnails and Textures15.db from a "master" client to "slave" clients and keep all of them in sync. I'm using MySQL for the library, so that takes care of centralising meta-data, but otherwise you might be able to sync the other MyMusic/MyVideo databases from the master to slaves, as that might also work. Maybe. Definitely not tested, etc. etc.
One other wrinkle with NFS booting on OpenELEC, is that connmand (the network connection manager) on the Pi will write to syslog (/var/log/messages) every 17 minutes as it updates the time (ntp). Since the logs are now located on the NAS, this log activity prevents the NAS from spinning down its disks. So, to silence ntp and allow the NAS to spin down its disks you can add the following to each Pi:
1) In .config, "cp /etc/syslog.conf ."
2) edit ./syslog.conf so it looks like the following - basically, we're adding an entry for the daemon.info facility (used by ntp) so that log entries are written to /dev/null (ie. discarded):
3) Create an autostart.sh job that will restart syslogd with our new config:
4) chmod +x ./autostart.sh
Now, ntp updates will be discarded, given the NAS the opportunity to spin-down its disks when RPi clients are idle.
Performance is very good, even booting is only marginally slower than SD card (about 35 seconds with class 10 SD card, 40 seconds over NFS with ancient pre-Class system SD card).
Just create the NFS share with "All Directories" ticked, "Maproot User == root" and "Maproot Group == wheel". Once created, you should have an entry in /etc/exports similar to the following:
Code:
/mnt/share/OpenELEC -alldirs -maproot=root:wheelThen within the share, create a "System" and "Storage" folder.
Within the System folder, copy in the OpenELEC SYSTEM file. That's all that needs to be in there. However, if you have multiple clients it might make sense to create individual client folders within the System folder so that each client can auto-update at their own pace (clients running older firmware may break if they pick up a newer SYSTEM file). So with multiple clients, create rpi#1, rpi#2 folders and within each of those folders copy in the SYSTEM file.
Within the Storage folder, if you have multiple Pi's you should create further sub-dirs for each client, eg. rpi#1, rpi#2 etc. Leave the folder empty so that it will be initialised by the R-Pi - later on you can create a backup and duplicate it for new clients (eg. restore a busted client back to "known good state" etc.).
On the Pi SD card, create a single FAT partition with the following files from the OpenELEC package:
Code:
bootcode.bin
cmdline.txt
config.txt
fixup.dat
kernel.img
loader.bin
start.elfNote that you no longer require the SYSTEM file on the SD card, meaning the SD card can be as small as 8MB (though 16MB would be a more sensible minimum). Performance of the SD card is also now largely irrelevant, as it's only required during boot (and when updating the system software - a rare occurrence under normal circumstances).
Set config.txt to your own requirements (overclocked, gpu mem etc. etc.).
For cmdline.txt, specify the following to enable NFS booting (make sure it's all on one line):
Code:
ip=dhcp netboot=nfs boot=NFS=192.168.0.200:/mnt/share/OpenELEC/System/rpi#1 disk=NFS=192.168.0.200:/mnt/share/OpenELEC/Storage/rpi#1 nomodeset ssh debuggingwhere 192.168.0.200 is my FreeNAS server - change to match that of your own server, also the NFS mount point.
Then boot your Pi, as that's all there is to it.
Unfortunately (as of OpenELEC Beta 6), auto-update is not currently working correctly with NFS boot (issue #1653) but other than that, NFS booting is a pretty good solution as it makes the system a lot more resilient to SD card corruption (since there are now no SD card writes, except when updating system software - disable auto-updates to prevent ALL SD card writes), boot performance is still very good, you can use any old SD card (even the smallest, slowest you have lying around - no need for uber-fast or large capacities etc.), and it simplifies backups and new client setup (just duplicate the Storage folder of an existing client).
Conceivably, a simple cron job running on the FreeNAS server could be used to rsync the Thumbnails and Textures15.db from a "master" client to "slave" clients and keep all of them in sync. I'm using MySQL for the library, so that takes care of centralising meta-data, but otherwise you might be able to sync the other MyMusic/MyVideo databases from the master to slaves, as that might also work. Maybe. Definitely not tested, etc. etc.
One other wrinkle with NFS booting on OpenELEC, is that connmand (the network connection manager) on the Pi will write to syslog (/var/log/messages) every 17 minutes as it updates the time (ntp). Since the logs are now located on the NAS, this log activity prevents the NAS from spinning down its disks. So, to silence ntp and allow the NAS to spin down its disks you can add the following to each Pi:
1) In .config, "cp /etc/syslog.conf ."
2) edit ./syslog.conf so it looks like the following - basically, we're adding an entry for the daemon.info facility (used by ntp) so that log entries are written to /dev/null (ie. discarded):
Code:
# all daemon.info to be discardded - ntp etc.
daemon.info /dev/null
# all messages of kern and user facilities
kern,user.* /var/log/messages
# all messages of kern facility with priorities lower than err (warn, notice ...)
kern.!err /var/log/critical
# all messages with auth and authpriv facilities
auth,authpriv.* /var/log/auth3) Create an autostart.sh job that will restart syslogd with our new config:
Code:
#!/bin/sh
# Restart syslog with modified syslog.conf - avoid logging ntp every 17 minutes
SYSLOG=$(ps aux | grep "syslogd$" | grep -v grep | awk '{ print $1 }')
if [ -n ${SYSLOG} ]; then
kill ${SYSLOG}
syslogd -f /storage/.config/syslog.conf &
fi4) chmod +x ./autostart.sh
Now, ntp updates will be discarded, given the NAS the opportunity to spin-down its disks when RPi clients are idle.