RE: iperf / ftp / http TCP poor performance in one direction (UDP good)

Hi - What do you mean by "read test"? hdparm?

hdparm -tT /dev/sda1

/dev/sda1:

Timing cached reads: 8412 MB in 2.00 seconds = 4207.53 MB/sec

Timing buffered disk reads: 190 MB in 1.94 seconds = 97.96 MB/sec

# hdparm -Tt /dev/sda3

/dev/sda3:

Timing cached reads: 7400 MB in 2.00 seconds = 3703.93 MB/sec

Timing buffered disk reads: 186 MB in 3.02 seconds = 61.58 MB/sec

ftp (With ss)

ESTAB 0 477840 ::ffff:192.168.123.2:ftp-data ::ffff:192.168.123.1:51161

ESTAB 0 360552 ::ffff:192.168.123.2:ftp-data ::ffff:192.168.123.1:51161

And results (Similar to iperf):

ftp> get 64Mb.zip

local: 64Mb.zip remote: 64Mb.zip

200 PORT command successful

150 Opening BINARY mode data connection for 64Mb.zip (67108864 bytes)

226 Transfer complete

67108864 bytes received in 42.11 secs (1556.2 kB/s)

Date: Fri, 12 Apr 2013 11:08:23 +0200
Subject: Re: iperf / ftp / http TCP poor performance in one direction (UDP good)
From: emi2fast@gmail.com
To: johnelliot67@hotmail.com
CC: mtzguido@gmail.com; debian-user@lists.debian.org

Hello John

Try to do read test on the sender, if you don't find any read problem try to do a transfer using ftp

Thanks

2013/4/12 John Elliot <johnelliot67@hotmail.com>

Thanks for the reply:

ss results (wget in "bad" direction):

"Receiver" - Recv and Send does not change from "0":
ESTAB 0 0 192.168.123.1:32815 192.168.123.2:www

"Sender" - snapshots below:
State Recv-Q Send-Q Local Address:Port Peer Address:Port

ESTAB 0 505352 192.168.123.2:www 192.168.123.1:32816

ESTAB 0 522728 192.168.123.2:www 192.168.123.1:32816

ESTAB 0 328696 192.168.123.2:www 192.168.123.1:32816

In the other direction:

Reciever:
ESTAB 0 0 192.168.123.2:33036 192.168.123.1:www

Sender:
ESTAB 0 535760 ::ffff:192.168.123.1:www ::ffff:192.168.123.2:33038
ESTAB 0 383720 ::ffff:192.168.123.1:www ::ffff:192.168.123.2:33038

ESTAB 0 474944 ::ffff:192.168.123.1:www ::ffff:192.168.123.2:33038

Date: Fri, 12 Apr 2013 10:06:38 +0200

Subject: Re: iperf / ftp / http TCP poor performance in one direction (UDP good)
From: emi2fast@gmail.com
To: johnelliot67@hotmail.com
CC: mtzguido@gmail.com; debian-user@lists.debian.org

Hello

Maybe it can the the disks write speed, anayway you can use netstat or ss
look for Recv-Q Send-Q columns

2013/4/12 John Elliot <johnelliot67@hotmail.com>

Thanks again for your help with this.

I've run 500 pings (-c 500 -i 0) in both directions, and got zero loss.

Ill try running tcpdump on both servers, and re-testing to check the segments.

Swapping the servers would be extremely difficult ;) (They are over 1000k's apart, and one is in an unmanned(majority of the time) data centre.

> From: mtzguido@gmail.com
> Date: Fri, 12 Apr 2013 01:38:40 -0300
> Subject: Re: iperf / ftp / http TCP poor performance in one direction (UDP good)
> To: johnelliot67@hotmail.com
> CC: debian-user@lists.debian.org

>
> On Fri, Apr 12, 2013 at 1:16 AM, Guido Martínez <mtzguido@gmail.com> wrote:
> > Did you check if A acknowledges every received segment?
> Sorry, what I meant by this is if every sent segment from B reaches A.
> You can run an instance of wireshark on each host to check this.
> Basically you need to check for packet loss at high speeds (ping could
> be of use if you set the interval to 0).
>
> TCP Dup ACKs are likely caused by packet loss.
> TCP segment of a reassembled PDU is something Wireshark adds since it
> interprets a bit about application layer protocols, and I think it's
> not a reason to worry (I could have understood this wrong, I just
> looked it up).
>
> If it's easy, you could also try swapping the location of the hosts,
> to see if the problem is on the hosts, or on the link.
>
> Hope it helps and post more info if you find any.
> Guido
>
>
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--
esta es mi vida e me la vivo hasta que dios quiera

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esta es mi vida e me la vivo hasta que dios quiera