I've setup a fresh Debian Squeeze on an old, unused notebook and wanted to use it as a file server. A large (1.5 TB) USB harddisk attached serving as the main storage.
When everything was running, I made some speed tests over smbfs (Samba), and saw that using "rsync -av --progress", it displayed ~20MB/s, but then dropped and in the end, I got a maximum of 900-1000 kB/sec (!) transfer speed.
First I suspected my smb.conf to be wrong, so I tried rsync-over-SSH: same speed.
Then I noticed a huge number of ethernet collisions on my hub (yes, a hub...) - so I replaced it with a switch: Same speed!
After suspecting the lousy SiS900 ethernet chipset to be the cause, I ended up debugging it with mii-tools, etc.
I've even checked the interrupts (cat /proc/interrupts) and moved the HDD to another USB, as eth0 and ohci_usb1 were sharing the same IRQ.
No success. Same speed
[SOLUTION]
Then it suddenly occured to me: USB!! O-H-C-I USB!
The notebook only had USB 1.1 ports (ohci driver), with a maximum of 12MBit - which translates to roughly 1000 kB/sec.
I've switched to a newer (still old) notebook with USB 2.0 ports for the job.
Why did I write this down? So, that maybe someone else won't lose that much time, by overlooking something obvious like this
