Local network speed issues, 12.04.01/smb/cifs

Question

I have some very common setup:

• a file server box (12.4.1 / kernel 3.6 / kde) connected to a router box (inet, dhcp).

Wi-Fi router is connected to the first one as DHCP relay. Both are not the best ones, but relatively new; b/g/n modes.

• and devices; like a laptop under latest mint with 3.6 kernel, connected to AP.

All devices are on the same network.

When I run iperf, I have speed between them two = 70 Mbit/sec.
When I use samba, a big file is copied at 3.4 Mbit/sec.
When I mount same thing with cifs, a big file is copied at 10.4 Mbit/sec.
Ping in between ~3ms.

I haven't tried NFS yet, will do. But the question is: why would the network speeds differ THAT much?

I would expect 2x drop, or say 4x drop for some whatever bidirectional something, but that is 20x downspeed - with samba.

Is it likely something wrong with my setup - or is it some expected result?

I have couple Windows laptops and would prefer to use something easy compatible like samba - but in my 12.4.1 setup smbd crashes few times a day for pattern I could not identify - and "service restart" does not help, so I have to reboot. Smbd and nmbd logs do not show anything significant. That did not happen in 11.10.

Now the other question is: should I keep fighting samba setup, or should I consider some other file sharing option that is easy with Windows?

Googling did not show any obvious alternative to samba. There is no big load needed on the box - a few guys sharing it as programming/apache/php/etc server, so it just needs to be reasonably quick and reliable.

Answer 1

Disk performance and network performance are different beasts. iperf measures network performance, ie, data speed over LAN. Since there are no disk reads (and, specially, writes) involved, performance is expected to be many times greater than any file copy. That explains the 70MB/s vs 10MB/s (or 3) difference.

As for "samba vs cifs": first of all, you may have noticed that their performance is "similar", at least in order of magnitude. One is "only" 3x slower, not 20x. And the reason is cifs is implemented by the kernel itself, natively, thus much faster than any other fuse-like, user space mount.

Good news is: you can use cifs to mount devices with the SMB protocol, so your shares are available to windows users. This way you get the best of both worlds: compatibility and speed.

An amazing guide from samba.org itself is this: CIFS Users Guide. You may also read their great wiki

That said, a wireless file copy speed of 10MB/s is, from my point of view, very nice.