On Fri, 18 Mar 2016 12:44:30 -0600 (MDT) "John L. Ries" <jr...@salford-systems.com> wrote:
> I don't know if it will help, but I hook up my Iomega NAS directly to my > desktop machine with a regular cat 5/6 cable (each has two gigabit > Ethernet ports, so each can connect to the rest of my network, as well > as to each other) and that seems to help the throughput by a lot (but I > don't have any numbers for you). So if your NAS has an extra Ethernet > port, you might want to hook it up to your laptop when you're in the > same room with it and use your wifi interface to connect to your > network. Certainly, you should avoid connecting to your NAS over wifi > if you're using it heavily, as that will definitely slow things down (it > seems that a lot more handshaking is required to connect through the air > than through a physical cable). Thanks. Currently, the NAS is used only as a backup target, so it's not a big deal - I'm mostly just frustrated and curious ... > On Friday 2016-03-18 10:48, Celejar wrote: > > >Date: Fri, 18 Mar 2016 10:48:24 > >From: Celejar <cele...@gmail.com> > >To: debian-user <debian-user@lists.debian.org> > >Subject: Throughput riddle > > > > Hi, > > > > I'm trying to understand the throughput across the different links of > > my little home network, and am perplexed by the measured wireless > > throughput. > > > > The three main devices I'm interested in: > > > > Router: Buffalo WZR-HP-G300NH running OpenWrt (Chaos Calmer 15.05). > > Gigabit WAN and LAN, 802.11bgn wireless. > > > > https://wiki.openwrt.org/toh/buffalo/wzr-hp-g300h > > > > Laptop: Thinkpad T61 running Jessie 8.3. Gigabit ethernet, 802.11abgn > > wireless. > > > > NAS: Seagate GoFlex Net [STAK100] runninng Debian Jessie 8.3. > > > > https://archlinuxarm.org/platforms/armv5/seagate-goflex-net > > > > All throughput measurements taken with iperf (run three times and using > > the median result), unless specified otherwise. These first results are > > with the laptop connected to the router via cat5: > > > > Laptop - NAS: ~874 Mbps. > > > > I suppose this is close enough to the gigabit theoretical max, and there > > isn't > > any significant bottleneck. > > > > Router - NAS: ~217 Mbps > > Router - laptop: ~198 Mbps > > > > Here the router CPU is apparently the bottleneck (top shows close to > > 100% CPU utilization by iperf for at least part of the 10 second iperf > > runs). I suppose that this is due to the bits needing to be copied out > > of the kernel networking stack into iperf's userspace memory, or > > something like that. I don't understanding why the NAS seems to be > > doing better, but I suppose it could be an artifact of the data. > > > > Here's the part that baffles me - these are with the laptop connected > > to the router wirelessly: > > > > Laptop - router: ~11.8 Mbps > > > > These numbers actually exhibit significant variance, but they're > > generally at least this much, and at most about 15-20 Mbps. > > > > Laptop - NAS: ~14.7 Mbps > > > > Once again, these numbers vary widely, but are in line with the laptop > > - router numbers. > > > > But here's the kicker: Ookla's speedtest (run on the laptop with > > speedtest-cli) shows 29.01/5.89 (d/u), and this is fairly consistent. > > I'm paying Comcast for 25/5, and they apparently provision at > > 31.25/6.25, so I'm getting quite close to the theoretical max, even > > when the laptop is connected to the router wirelessly. Additionally, > > various Android phones also get close to the Comcast provisioned max > > when connecting wirelessly to the router. > > > > So the wireless link can apparently push at least 30 Mbps or so, so why > > are my local wireless throughput numbers so much lower? > > > > I was originally using one of the common 1/6/11 channels, and I switched > > to 3 since I saw a lot of other stations on those channels. This may > > have resulted in some improvement, but I'm still stuck locally as > > above. What's the explanation for this - how can I possibly be getting > > much better throughput to servers tens of miles away than to my local > > stations? Does iperf somehow work fundamentally differently from > > speedtest? If so, which is a better representation of actual throughput? > > > > Celejar > > > > Celejar
