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Slow Performance Replicating Pool to Second TrueNAS Tethered Over Ethernet


Apr 15, 2015
I setup a second TrueNAS box (T2) to act as a backup for my main TrunNAS server (T1). I connected T1 to T2 on a separate ethernet ports via cat5 cable and set static IP addresses on each machine. I am able to setup a SSH connection for a replication task and start a backup. My issue, however, is the speed. Both ethernet interfaces are gigabit and work at that speed when connected to a network. When I tether T1 and T2, TrueNAS reports them at 100mbps. Also, the performance is poor at about 11mbs. If I setup a separate SSH connection over my gigabit network, I get speeds of about 80mbps. Just wondering why performance over a direct ethernet connection is so poor and if I can get TrueNAS to recognize the interface cards at full speed. I did try a different ethernet cable with the same result. Any guidance would be appreciated.

Thank you


Wizened Sage
Jan 1, 2016
Maybe this will get you somewhere:

Be aware that if you follow down to making it permanent, you will need to convert the editing of rc.conf into tunables in TrueNAS or they will be lost at each reboot.

It may also be possible to edit the interface in the GUI under Network | Interfaces and add in the "Options" item "media 1000baseTX mediaopt full-duplex"... no idea if it will work, but it seems to indicate that's the official place to do it.
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