If you use two Linux Servers with NFS Shares connect over Gigabit Interfaces for Backups, you perhaps remark performance problems on using rsync.
It does often pause transmissions or reach only a rate of 32Mb/s. That’s bad and waste time and energy.
After some Tests of running Backups with single files and compressed big archives, the scans of my tools like iftop, systat, iptraf found out that the used Option „rsync -avz“ was the bottle neck, cause the Data Rate break down at intervals. The „z“ compress option was described on howtos as must have for slower networks did not work like a „on the flypermanent transmission“. My two Test Servers use each 3 Gigabit bonded NIC Cards, if the rsync command compress the Files, they were first pulled to RAM Cache and compressed there later after a small pause send.
If you disable and remove the „z“ option and on used bash scripts as „batch run“ removing the „v“ Option too, i was able to send Data at range of 133MB/s.
Today the count of network devices at home networks grows up weekly, cause more and more home devices like freezers, coffee engines, dishwasher and more got builtin wifi interfaces. To have a Control Unit you can use a raspberry pi2 as cheap Network Monitor Logger.
The Raspian by default offers builtin free tools, like arp, arp-scan, nmap, ping to easy monitor a network. If you have learned some commands and the bash scripting you can fast create a Network Logger, perhaps with analyse tools to mail alerts if new „MAC“ NIC Adresses are seen. Every network device uses a owned MAC-ID like „00:d0:23:09:df:XX“. Thats like a car chassis number.
How to Setup:
Install Raspian (Debian) on a SDCARD for PI2
Boot the PI2 to Raspian
Upgrade the OS
Install lighttpd as Webserver for Outputs and start him
Install the Networktools „arp, arp-scan, nmap, ping“
Edit root crontab to run the commands every minute like „* * * * * /usr/sbin/arp-scan -l -I eth0 > /var/www/arp1/2-scan.log“
Open a webbrowser to http://pi2/arp-scan.log #You should see the Text like inside the Image
write a bash script with the „diff“ or „md5sums“ command to check the arp1-scan.log against the arp2-scan.log if any changes you can output a mail thru exim4 mailserver..
Advantage? A Pi2 is a powerful LAN WATCHDOG with 1Watt/hour and Mail Output Support to your devices! for free..