Optimize LAN usage with 2 NAS4free units

[riki]

Hello all,
I recently acquired a second NAS unit, and I installed NAS4Free on this second unit, so both nas01 and nas02 are running NAS4Free. Both nas01 and nas02 have two LAN adapters. Until now, I have been using only one adapter on the nas01 unit. However, I'm thinking of using the second adapter on both units so they will be able to do things quicker, at least between themselves: rsync (backup of the backup), bulk file transfers etc. I'm considering running an ethernet cable straight from one unit to the other, leaving the first adapters connected to the home LAN switches as they are now.

There are a few things I've thought about:

1) Allowing jumbo frames only on the "second" adapters (so they don't wreak havoc with the rest of my home LAN, which isn't, and won't foreseeably be, jumbo-ready). The first adapters, already in use, will keep the current normal MTU.

2) I suppose I'll have to set the second adapters to IP addresses in a different LAN.

3) Is there any simple way to tell both units "look, the machine at 192.168.1.10 is actually the same you'll find at 192.168.2.10", so that each of them chooses the "direct route" (with straight ethernet cable, no switches, jumbo frames) when talking to the other?

Please tell me if I'm way off reality Thanks for the help!

[riki]

I've researched around a little, and it seems there might be a solution involving routing tables. Not really sure it will work, and even if it does, I still can't figure out if the solution allows jumbo frames between the two NAS units.

I won't be able to test this for a week or more: my main unit has a dead motherboard (warranty, luckily!) and I'm waiting for a replacement.

Maybe I posted my question to the wrong subforum?

[ChriZathens]

I personally don't see why it shouldn't work..
Including jumbo frames..
After all you can tell rsync to use a specific IP
There is a possibility that you'll need each machine to be each other's gateway.
I highly doubt you will have any real benefit by doing this, though, but certainly give it a try.
I assume you want to use a cross cable, right?

[riki]

Hello ChriZathens, thanks for your reply.
I assume I'll need a cross cable, but I thought most modern adapters would switch automagically according to the cable (cross or regular).

I haven't found any explicit ready-made solutions, so I'll have to study and test my way, probably mid June. Hope I won't have to ask too many noob questions here then - assuming it's actually the right subforum