But with a serious loss of functionality. Given the internet connection that I have (cellular) I can’t reasonably set it up to do live streaming. I’ve also disabled interaction with the cam. What’s left is an image uploaded every hour. Not super duper cool but I’ll take what I can get in this neck of the woods.
Hopefully this will get better when better internet is available.
Sending ZFS snapshots across the wires can be done via multiple mechanisms. Here are examples of how you can go about it and what the strengths and weaknesses are for each approach.
strengths: encryption / 1 command on the sender
weaknesses: slowest
command:
zfs send tank/volume@snapshot | ssh user@receiver.domain.com zfs receive tank/new_volume
strengths: pretty fast
weaknesses: no encryption / 2 commands on each side that need to happen in sync
command:
on the receiver
netcat -w 30 -l -p 1337 | zfs receive tank/new_volume
on the sender
zfs send tank/volume@snapshot | nc receiver.domain.com 1337
(make sure that port 1337 is open)
strengths: fastest
weaknesses: no encryption / 2 commands on each side that need to happen in sync
command:
on the receiver
mbuffer -s 128k -m 1G-I 1337 | zfs receive tank/new_volume
on the sender
zfs send tank/volume@snapshot | mbuffer -s 128k -m 1G -O receiver.domain.com:1337
(make sure that port 1337 is open)
strengths: 1 command / encryption
weaknesses: seems CPU bound by SSH encryption, may be a viable option in the future?
command:
zfs send tank/volume@snapshot | mbuffer -q -v 0 -s 128k -m 1G | ssh root@receiver.domain.com 'mbuffer -s 128k -m 1G | zfs receive tank/new_volume'
Finally, here is a pretty graph of the relative time each approach takes:
SSH + MBuffer would seem like the best of both worlds (speed & encryption), unfortunately it seems as though CPU becomes a bottleneck when doing SSH encryption.
Here’s a script I wrote whose purpose is to discover the printers that are currently being advertised by Bonjour on the network. The reason I wrote it was for a Nagios check that would in term verify that our printers were present. Writing it took me through the meanders of MDNS in Python & on Linux with multiple vlans. Let’s just say non-trivial.
Download
Sample output
