[Bioclusters] gigabit ethernet performance

Tim Cutts bioclusters@bioinformatics.org
Fri, 9 Jul 2004 16:35:31 +0100

On 9 Jul 2004, at 2:57 pm, Justin Powell wrote:

> I can move a 1 Gb file between one dell dual xeon box and another in 44
> secs on my network (23MB/sec) using scp, but if I move from a dell to a
> dual G4 xserve local drive it takes 83 secs (12 MB/sec).

Try some protocol other than scp.  scp's limiting factor tends to be 
CPU, because of the encryption overhead.

> Strangely though
> if I move it from the dell to the Xraid attached to the G4 it also only
> goes at 12 MB/sec - and in that case the mac drive speed should not be 
> the
> limiting factor.

No, the CPU probably is.  The G4 is not that quick, and is having to do 
all that ssh decryption.  Try FTP instead.

Having said that, I have a sneaky feeling that the HFS+ filesystem is 
not the fastest in the world.  There is a SourceForge project to 
provide ext3 support to MacOS X.  I have not been brave enough to try 
it yet.  I downloaded it, and then chickened out.  :-)


Dr Tim Cutts
Informatics Systems Group, Wellcome Trust Sanger Institute
GPG: 1024D/E3134233 FE3D 6C73 BBD6 726A A3F5  860B 3CDD 3F56 E313 4233