Synology DS415+ Adaptive Load Balancing

UPDATE: I had a discussion with Ulrik D. Hansen, developer of NAS performance tester and thanks to some input from his side realized that test results described in this blog post are not correct, but I will leave this post as is and write another one with new tests and some explanations soon.

It is something like on year since I’m using Synology DS415+ NAS. This particular model has 2 Gigabit Ethernet ports with support for network load balancing and fault tolerance options, i.e. allow you to do link aggregation. This feature was one of the important things when I selected this particular model. Unfortunately when I tried this I realized that I cannot do load balancing as it required support for 802.3ad LACP from network switch. After quick research I found out that SOHO WiFi access-points doesn’t have advanced switching capabilities and normally limited to 4 Ethernet ports, unless you are ready to try to do some unsupported tweaks with alternative firmware. Unfortunately this is the case even for newest models of premium segment, including even one I’m aiming to buy soon (ASUS RT-AC5300). The thing is that they normally try to max out/beef up device wireless capabilities and feature keeping built in switching capabilities simple – and I can understand it, as wired connection is always way faster than fastest possible WiFi and by no means is primary feature of WiFi access points. But buying more advanced switch makes sense anyway, but I will cover this later.

So because of need for buying new switch I abandoned idea of using link aggregation with my Synology DS415+ as something I can’t do with equipment I have… And to be honest I somewhat missed the fact that in DSM 5.2 update Synology added support for two new modes when creating a bond interface: Adaptive Load Balancing and Balance XOR (see Synology DSM release notes). Only recently I tested this and indeed it works: you just create network bond and enable Adaptive Load Balancing option – nothing is required on your switch side:

NAS Enable Adaptive Load Balancing

Once enabled your network bond properties will drastically improve your mood if you are person who cares about performance ratings & large figures… 🙂 It’s a shame that we no longer have performance index in recent Windows releases (starting from Windows 8) and 3DMark tests fall out of fashion – you may argue about relevance of indexes/numbers and synthetic tests but we can’t argue that it was fun/enjoyable to have these things 🙂 Sad to see that we sort of moving away from universal bench-marking software, but it seems that the state of hardware ecosystem makes many of these tests irrelevant.

NAS ALB Bond properties

I looked around the net for feedback whether enabling this thing gives you real advantage or not & found a lot of pessimistic stuff like you never ever going to leverage this because of XYZ or because of the fact that XYZ will be a narrow place etc. So people really confused if there is some real gains from using this. Common sense answer to that – it all depends (on specific workload/scenario you are interested in). But whenever performance subject is raised for discussion, baseline is everything – luckily enough I did some basic performance tests without Adaptive Load Balancing (NAS connected over single Gigabit Ethernet port) some time ago. So now I can do at least some comparison. Of course this is not super clean comparison: I have newer DSM version on NAS (which may contain some improvements) and my target volume if formatted as ReFS – so those are differences. But still improvement way beyond any test inaccuracy as you will see below.

Test 1. NAS performance tester using 400 MB file with both header and data digests disabled.

Single gigabit Ethernet link:

Two gigabit Ethernet links with Adaptive Load Balancing enabled:

NAS Test 400MB

Test 2. NAS performance tester using 8000 MB file with both header and data digests disabled.

Single gigabit Ethernet link:

Two gigabit Ethernet links with Adaptive Load Balancing enabled:

NAS Test 8000MB

So to sum this up, we see real performance increase here:

NAS ALB tests result

So despite the fact that laptop from which I run this test connected only over single Gigabit LAN port we see substantial performance gains. But what if instead of plain simple switch I have built-in into my WiFi access point we add big managed switch? So I’m expecting to get one on next week with switching capacity 36 GB/s (26.79 GB/s max forwarding rate) and do some more tests – the same Adaptive Load Balancing config while connected through this dedicated switch and later another test of 802.3ad link aggregation mode (switch I’m going to get is D-Link DGS-1100-18 from DGS-1100 Series of Gigabit Smart Switches). Stay tuned if you interested to see tests results.


  • Toby says:

    so, how does 802.3ad link aggregation mode compare?

    • Mikhail says:

      Well still didn’t get around to configure/compare. But based on what I read so far – LACP/802.3ad is switch dependent not only because you need switch side support for this standard but also because you have to use ports on the same switch (probably you can go beyond that with stackable switches/some smart models) which is essentially introduces single point of failure to your environment (switch). Yet any switch independent config needs some hash or other calculations to be performed so probably adds a bit of overhead (=slower). But still need to test this.

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