samba3 performance vs samba2

[tridge at samba.org]

Tang,

 > samba2.x  read:  2.178037MBps	write: 2.227366 MBps
 >  samba3.20b read 1.942255MBps	write 1.886527 MBps
 > 

I doubt your results really are accurate to 7 digits. Did you measure
the varience between runs? That might give us an idea of what the true
discrepancy is.

 >   my question is why samba3.20b is a bit slower in the same
 >   environment as samba2.x. does samba3 do some extra work? How to
 >   tune samba3 to achieve a similar performance as samba2.x?

a few parameters changed their default value in Samba3. For example,
"strict locking" is now on by default, whereas it used to be off by
default. This makes Samba3 more accurate to the way a SMB/CIFS server
is supposed to behave, but also makes it a little bit slower (as on
Posix systems it means you have to do extra system calls on every IO).

Cheers, Tridge