I am having some problems with network performance speed on a Linux server running Ubuntu 9.10. Transfer speeds on all types of traffic are around 1.5MB/s on a 1000mbit/s wired ethernet connection. This server has achieved 55MB/s over samba in the recent past. I have not changed the hardware or network set-up. I do run updates on a regular basis and the latest and greatest from Ubuntu's repositories is running on this machine.
Desktop Windows PC - 1000 switch - 1000 switch - Linux server
All switches are netgear, and they all show a green light for their connections which means the connection is 1000mbit/s. The lights are yellow when the connection is only 100mbit/s. Other diagnostic information:
root@server:~# ifconfig eth0 Link encap:Ethernet HWaddr 00:0c:6e:3e:ae:36 inet addr:192.168.1.30 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::20c:6eff:fe3e:ae36/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:28678 errors:0 dropped:0 overruns:0 frame:0 TX packets:73531 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:2109780 (2.1 MB) TX bytes:111039729 (111.0 MB) Interrupt:22 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:113 errors:0 dropped:0 overruns:0 frame:0 TX packets:113 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:23469 (23.4 KB) TX bytes:23469 (23.4 KB) root@server:~# ethtool eth0 Settings for eth0: Supported ports: [ TP ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Supports auto-negotiation: Yes Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Advertised auto-negotiation: Yes Speed: 1000Mb/s Duplex: Full Port: Twisted Pair PHYAD: 0 Transceiver: internal Auto-negotiation: on Supports Wake-on: pg Wake-on: g Current message level: 0x00000037 (55) Link detected: yes root@server:~# mii-tool eth0: negotiated 1000baseT-FD flow-control, link ok
The server thinks its got a 1000mbit/s connection. I have tested the speed of transfer by copying files using Samba. I have also used netcat (nc target 10000 < aBigFile) on the server to transfer to Windows (nc -l -p 10000) and saw similar levels of poor performance.
I tested the speed of the hard drives using hdparm and got:
root@server:~# hdparm -tT /dev/md0 /dev/md0: Timing cached reads: 1436 MB in 2.00 seconds = 718.01 MB/sec Timing buffered disk reads: 444 MB in 3.02 seconds = 147.24 MB/sec
Reading the same file for transfer using DD produced the following:
paul@server:/home/share/Series/New$ dd if=aBigFile of=/dev/null 3200369+1 records in 3200369+1 records out 1638589012 bytes (1.6 GB) copied, 12.7091 s, 129 MB/s
I am stumped. What could be causing the poor network performance which is 2 orders of magnitude lower than what the network is capable of?