Gentoo Archives: gentoo-user

From: YoYo siska <yoyo@××××××.sk>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] How to determine if a NIC is playing gigabit?
Date: Mon, 18 Jan 2010 12:29:58
In Reply to: [gentoo-user] How to determine if a NIC is playing gigabit? by Stroller
1 On Mon, Jan 18, 2010 at 11:50:55AM +0000, Stroller wrote:
2 > Hi there,
3 >
4 > Yesterday I reseated the network cable between my server cupboard and my
5 > desk, and it now lights up on the switch by my desk as gigabit. But a
6 > file-transfer today is slower than I might have hoped.
7 >
8 > I'm not ruling out the cable, because it's pretty beat up (but the
9 > switch *is* lighting up as 1000), but how do I determine, please, that
10 > the Linux server at the other end is recognising the NIC and negotiating
11 > as gigabit speeds?
13 mii-tool (net-tools) or ethtool should be able to tell you that
16 > The hard-drives on the server are using an older PCI SATA card, and the
17 > NIC is also PCI. But I would have expected it to be a bit faster than
18 > 100Mbps.
19 >
20 > Any estimates over what kind of speed I should be seeing for large
21 > file-transfers over Samba? Wildly ball-park is fine - I wouldn't expect a
22 > 10x speed increase, but maybe 2x or 3x - 4x would be great!
24 don't know about samba, but with scp or nfs I can get about 20MByte/s which is
25 the speed of my disk (and for scp almost what my cpu can manage ;)
26 scp-ing /dev/zero gets me something short of 30MBye/s but that is
27 because my CPU cannot manage more ;)
29 You can see an estimate of your "raw" speed between the two machines by
30 running
31 nc -l -p 7777 | pv >/dev/null
32 on one computer and
33 pv /dev/zero | nc OTHER_COMPUTER 7777
34 on the other. I don't have a 1gbit switch here right now, so can't give
35 you an estimate (with two notebooks connected directly by cable I just
36 got 100MByte/s, which is near enough to the theoretical maximum ;)
37 (pv is like cat, but displays a progressbar with act. speed, sys-apps/pv)
39 you can also try netperf for more precise benchmarks
41 >
42 > I'll be testing between my Macs (both on the desktop switch, ruling out
43 > both the Linux box and the suspicious cable) later today, I'd just like
44 > some ideas of where I should be starting from.
45 >
46 > Right now I'm seeing 10 gigs of .mp4 files (1gb - 2gb per video file)
47 > taking about an hour - that's about what I'd expect from old 100Mbps
48 > networking, not this shiny new stuff.
50 hmm, that seems a bit low even for 100mbit, I have usually no problem getting
51 cca 10 MByte/s with 100mbit switches (without other traffic), though I
52 use either nfs or scp
53 the only time I remember using samba was with a winxp server, which
54 didn't go above 1MB/s, but I suspect that the problem was either on the
55 win side or some misunderstanding between win and linux ;)
57 >
58 > I'm not seeing any difference commenting & uncommenting "aio read size =
59 > 1, aio write size = 1" (separate lines) from /etc/samba/smb.conf and
60 > then running `/etc/init.d/samba reload`, but maybe I shouldn't expect
61 > that to make any difference on an existing transfer. I just don't want
62 > to interfere with this right now - I just want to copy as much as
63 > possible on to my laptop before I go out, and I'll take a look at this
64 > performance issue when I get home.
65 >
66 > Thanks in advance for any suggestions or pointers,
67 >
68 > Stroller.
69 >
73 yoyo