Hi,

I've been experiencing network speeds which I believe should be performing better. I have two linux machines connected via a 1Gb network. Performing file transfers will generally never exceed 25MB/s.

Using iperf, I get on average 89.2 MBytes/sec transfer results.

The disk's on both servers are fast enough to max this out. Average block write speed is 113MB/s (Tested with Bonniee++). To be 100% certain it wasn't the disk causing the issue, I created a RAM drive on each server, and copied files across the network from one RAM drive to the other. Network speeds again didn't exceed 25MB/s.

Generally using rsync over ssh to do file transfers, but also have samba shares setup which experience similar performance.

I've copied a file from the linux RAM drive over samba to a Windows machine and back at roughly 55MB/s. Copying that same file over samba from linux to linux happened at about 22MB/s. This would seem to indicate there's some sort of Linux to Linux bottleneck.

Both machines are running Fedora Core 10, using 2.6.27.24-170.2.68 kernel. One is x86_64 the other is i386.

Hardware Info
Machine #1
Intel Q6600
4Gb DDR2 RAM
4x1000GB in RAID5 using mdadm.
1GB Nic

Machine #2
AMD Athlon 4600+
2GB RAM
2x1500GB in RAID0 using mdadm.
1GB Nic

Any help appreciated.

That does sound a bit slow. Have you tried regular, un-encrypted FTP? I've read someplace that the encryption of doing rsync over ssh can actually add some overhead, slowing the transfer down (not sure if SAMBA adds encryption too, as I never use it). You might want to try plain jane FTP or NFS (or even rcp) to see if there is a difference. If it doesn't help, you might want to try tuning your TCP settings (particularly receive buffers and time outs). There are several guides on the Internet for this (and IBM has a performance tuning red book), but it's not something I've looked at recently, so I can't offer any more specific advice.