Can Samba get us there?

Cole, Timothy D. timothy_d_cole at
Wed Nov 3 22:55:13 GMT 1999

> -----Original Message-----
> From:	Laura Morse [SMTP:Laura_Morse at]
> Sent:	Wednesday, November 03, 1999 15:39
> To:	Multiple recipients of list SAMBA-TECHNICAL
> Subject:	FW: Can Samba get us there?
> > Are we asking too much of Samba?  Areas of concern include:
> > 
> > *	Disk Caching -   Reliability is of paramount concern.  And
> > reliability can only be obtained if all users have access to current /
> > correct information.  (It would be disaster if the DOS users and Unix
> > users were "seeing" different data).  When a user on 1 platform (DOS or
> > Unix) updates data, that data must be available to all other users
> > (regardless of whether the other users are on a same or different
> > platform)
	Not a problem, as long as oplocks are supported for your Unix OS
(currently only IRIX, afaiK), or you turn oplocks off.

	Since smbd is just a normal Unix process acting on behalf of the DOS
client, any file accesses it makes go through the same cache as file
accesses made by other software running on the Unix side.

	Cache consistency should not be a problem.

> > *	Memory Caching - Any data cached in the Unix memory (and therefore
> > unavailable?) to DOS users would cause unacceptable reliability problems
	What is the question, exactly?  Disk cacheing on the Unix side (this
question), versus cacheing on the client side (for the first question)?  See
above, I think.

> > *	Record / File Locking - Concurrent access to data must be managed
> > and controlled. FoxPro uses standard NetBIOS API calls to obtain Record
> /
> > File locks. Not sure what Recital does for locking on Unix (other than
> it
> > supports Record / File locking) - but we'd require Samba to handle the
> > 'translation' flawlessly.
	As long as Recital uses fcntl() locking (which I suspect it does,
since it does record locking), you should be fine.

	You will probably want to turn off the "OLE locking compatibility"
option, since it sounds like you won't be using Windows OLE applications,
and you get full locking granularity by turning it off.  

	From the manpage:

This parameter allows an administrator to turn off the byte range lock
manipulation that is done within Samba to give compatibility for OLE
applications. Windows OLE applications use byte range locking as a form of
inter-process communication, by locking ranges of bytes around the 2^32
region of a file range. This can cause certain UNIX lock managers to crash
or otherwise cause problems. Setting this parameter to "no" means you trust
your UNIX lock manager to handle such cases correctly. 

> > *	AIX - What special challenges does AIX present and are there known
> > solutions.
	I'm an HP-UX/Linux guy myself; however, as far as I know, there are
no significant issues for AIX.  Anyone with more AIX experience want to
field this one?

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