samba - Feb 2008 - Need to "net use \\someserver\someshare" to increase speed?

All,

We've been testing to determine why SAMBA access to UNIX clearcase VOBs
became slow when we upgraded from 2.2.8a to 3.0.14 (and now 3.0.24).  I
cannot say we've found 'anything new' but we have found the
following
behavior.  Any help understanding why a WinXP and Win2K client would
need the shares to VOB storage mapped to speed processing would be
appreciated (note that it works without the mapping just uses a process
per connection).  Or, perhaps there is a setting missing from smb.conf
or the Windows clients.  Thoughts?

For those unfamiliar with clearcase, cleartext is the text generated by
clearcase (from a base version with deltas) when a user wants to view a
pariticular version of a file.  There are 'scrubbing' parameters that
remove cleartext after it is unused for a period of time.  But, as long
as someone accesses it or the scrubbing is set to 'never' the need to
build cleartext is minimal.  Also, a snapshot view is a view where a
user requests particular versions of all files specified and clearcase
sends those files to the user's computer.  The user can then go offline
and work on those files and send the updates back to the VOB server when
finished (i.e. update the view).

My test snapshot view uses about 5000 files/120MB of data.

1. If there is no cleartext for a source container, a new connection
   will be opened and closed for each cleartext as it is created from
   source. 

   I stopped the test after an hour when only 645 files had been
   transferred. At that rate, it would have taken about 8-9 more hours



2. If the Windows client maps a drive to the Samba share, then a
   connection is kept open from client to VOB server and only one
   connection is used as cleartext containers are created from source
   containers. This speeds up the snapshot view loading dramatically. 

   It took about 30 minutes to load 5000 files/120MB. I consider this
   to be reasonable performance.


3. If the cleartext for the source container exists but no drive is
   mapped from the client to the Samba share, multiple connections
   are opened to transfer the files. However, instead of one
   connection for each files, several files 50-100 are transferred
   before the connection is closed an a new one opens

   It took about 9 minutes to transfer the 5000 files/120 MB


4. If the cleartext for the source container exists and a drive is
   mapped from the client to the Samba share, only one connection is
   used to transfer all of the data. 

   However, there was no significant difference in the time to
   transfer the data than the previous item 3. It took about 9 minutes
   to load the view.

5. There was no difference between

   3.0.14a -- security = ads
   3.0.14a -- security = domain
   3.0.24  -- security = domain

Thank you for suggestions,

Julie