Expected transfer rate of samba, SATA over gigabit to SATA
 

What is a good transfer rate to expect when writing from Windows XP/Vista to a samba network share in the following situation?

* New client. Intel Core 2 Duo 6600 with 4GB memory, and Intel gigabit NIC.
* New server. HP XW8400 with (currently) a single 5335 Xeon with 4GB memory, and integrated Intel gigabit. Running samba 3.0.25b, as included with CentOS (RHEL).
* Netgear GS116 (gigabit) switch

Using TTCP (on Windows PCATTCP) I get around 406Mbit/sec (50.75MB/sec) between the new client and new server. TTCP transfers random data between two computers, to purely test the network transfer rate -- not using either computer's hard drive whatsoever. This seems about right. From what I've read elsewhere, it appears gigabit typically performs at about 40% of it's theoretical transfer rate of 1000Mbit/sec unless very expensive switches and NICs are purchased.

Using hdparm, I get around 640Mbit/sec (80MB/sec) on both the client's SATA drive and the new server's SATA drive.

Transferring a 700MB AVI file from Windows to the samba network share runs between 75Mbit/sec to 280Mbit/sec (9.4MB/sec to 35MB/sec), ranging wildly. I am not sure why some of the files sometimes transfer so much slower than others. I have all other network traffic stopped, and am transferring different AVI files each time to eliminate a possibility of the client machine caching the file in memory -- since I have noticed that transferring a file a second time right after the first time often runs much faster.

I set up vsftpd as a temporary test, and transferring 700MB AVI files from Windows to the new server by ftp runs between 67Mbit/sec and 115Mbit/sec (8.4MB/sec to 14.4MB/sec).


Transfers to my old server of large files were often around 92Mbit/sec (11.5MB/sec). I was hoping to see a huge increase moving to the new server, because the old server ran a slow RAID5 of IDE drives, which hdparm only showed a 256Mbit/sec (32MB/sec) read rate from -- and the new server runs (currently) a single SATA drive which hdparm shows a 640Mbit/sec (80MB/sec) read rate from, just like the client's hdparm results on a SATA drive.


One of the new server's functions is to provide a backup service for customer machines. We copy the entire contents of a customer's hard drive to this backup volume temporarily. Should I be expecting to get (for large files) greater transfer rates than I am getting, or to go faster do I need to install a hot swap bay into the new server to transfer a customer's hard drive into?