why nfs is so slow?
kheuer2 at gwdg.de
Tue Dec 11 04:29:57 PST 2007
On Tue, 11 Dec 2007, Wojciech Puchar wrote:
> i'm getting about 6MB/s with NFS (100Mbit cross-connect ethernet), while over
> 9.5 by FTP.
> nfs is set to work over TCP.
To my mind, this is because NFS is stateless because of being designed to
share filesystem on a whole local network. Thus, every remote procedure
call (the basic NFS operation) is self contained. Thus, every single read
request causes the server to open the file, to read the number of bytes
requested, and to close the file.
If you compare this to a typical peer-to-peer ftp session, the overhead is
obvious. On the other hand, ftp is a very special application.
GWDG, Am Fassberg, 37077 Goettingen, Germany, kheuer2 at gwdg.de
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