Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have slow network transfer speed (26 MB/s). The beginning of the transfer started at 120 MB/s and dropped down every second.

I am transferring a 350 GB file from an E-Sata (7200rpm) drive mounted on Windows 7 to a Unbuntu Samba share (on esxi). The samba share is mapped to a drive letter on Win 7 by IP address.

ethtool eth0 shows:

Settings for eth0: Supported ports: TP Supported link modes: 10/100 half/full, 1000/full Supports auto-negotiation: Yes Advertised pause frame use: No Advertised auto-negotiation: Yes Speed: 1000MB/s Duplex: Full Port: Twisted Pair PHYAD: 0 Transceiver: internal Auto-negotiation: on MDI-X: Unknown Supports Wake-on: d Wake-on: d Current Message level: 7 link detected: yes

share|improve this question
up vote 0 down vote accepted

Just try to test disk for wtite speed with dd in linux. and then check your network with iperf. and you ll know where is a bottle neck.

share|improve this answer

The hard drive almost certainly only supports ~26MBps. Even the latest round of SATA drives can barely pull double that number (under idea conditions too).

That beginning speed of 120MBps isn't even really possible; 1000Mb / 8 * 80% = ~100MBps (realistic max). Windows caching is playing with the number, hence the high initial speed and after a while the number settles to the sustainable throughput.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.