[Samba] Gigabit Ethernet and samba network bandwidth

Alexander Sbitnev shuras at dezcom.mephi.ru
Thu Feb 19 14:56:58 GMT 2004

Hi all,
 I am notice strange behaviour of samba in our mixed
 fastEthernet/gigabitEthernet enviroment.
 First of all let me to describe our situation.
 We have a samba server running debian unstable with 2.6.3 kernel
 installed. Server has a gigabit copper connection (tg3 driver) to the
 100/1000 Megabit switch (3COM 4228G). Client is a WinXP/Linux workstation
 connected by ordinary 100 Megabit link to the same server doing a copy
 of a big file from server share.

 The problem is what copy speed in that case is very low.
 It's about 4-5 Megabytes per second (while 100 Megabits is expected).
 At the same time i've got about 90 Megabits data transfer with NTTcp
 (linux network benchmark) program. Ftp transfers are also going much faster.
 At the other side when i switched server link from gigabit to fastEthernet
 port of the same switch i got samba transfer speed about 9-10 Megabytes per
 second what's looks like a full fastEthernet utilisation.

 Our disk performance is quite good so there are only samba concerned
 network problem.

 Another our server connected to the other switch (DLink one)
 is stressed by about 50 real clients (WinXP,100Mbit) getting
 multimedia contents. Server total bandwidth reach 250 Mbits value and
 one client can't get more than 40 Mbits of samba bandwidth. At the same
 time same clients can have much faster transfer with ftp protocol.

 Is there any suggestion how to make samba faster? I think problem
 can be caused by samba protocol which according to a strace output
 performing client-server short data exchange after each 64K(?) transfer.
 Ftp protocol just feeding data from server to client without any
 additional exchange.
Best regards,
 Alexander                          mailto:shuras at dezcom.mephi.ru

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