Hi all,
I just purchased my first Mikrotik device - a CRS309-1G-8S+IN - and after a bit of a rocky start (had to RMA the device due to the PoE input dying on the second use) I finally have the replacement unit up and running.
Unfortunately, despite it being connected to my servers at 2x 10G links each, I can only get between 0.9G and 1.1G transfer rates and I can't work out why.
The device arrived with all 8 SFP+ ports plus the 1G port in a bridge configuration. I removed ports 1-6 and used them to create three bonded interfaces to get a 20G link to each of the three servers I wish to connect. Previously two of these servers were directly connected and I was able to get approx. 18G transfer between them. Now the CRS309 sits in between them with an additional set of 10G direct attach cables, but there's no other change. The bond interfaces are set to balanced-rr on both ends (the servers run Linux). ethtool reports all links at 10G on the server side, and the RouterOS web page reports all links at 10G on the Mikrotik side, so the physical side of things appears to be fine.
However now, with the three bonded ports (2x SFP+), two unconnected SFP+ ports, and the 1G Ethernet port, I can barely reach 1G between any two servers that should each have a 20G link. I expected to get at least 17G but not 0.9G.
I tried temporarily disabling the 1G port in case it was trying to send all traffic over it for some reason, but even with the 1G port disabled, the 20G bonded links could barely make 1G.
Obviously I've done something wrong as 1G isn't even close to the unbonded 10G single-link speed, let alone the 20G available from the dual link, but I've gone through all the menus and looked around online and can't see anything that could explain it.
I'm not using any routing features (one of the machines is a Linux server that's doing my routing) so I suppose I could give SwOS a try, but it doesn't seem right that RouterOS would perform so poorly. So I'd like to try to understand what I've done wrong before I give up and try the other OS.
Any ideas what I might have missed?