HP CIFS Server 3.0g Administrator's Guide verison A.02.03.01

• printer admin
• hosts allow
• hosts deny
• hosts equiv
• preload modules
• wins server
• vfs objects
• idmap backend
Other Samba Configuration Issues
Translate Open-Mode Locks into HP-UX Advisory Locks
The HP CIFS Server A.02.* versions can translate open mode locks into HP-UX advisory locks.
This functionality prevents HP-UX processes from obtaining advisory locks on files with
conflicting open mode locks from CIFS clients. This also means CIFS clients cannot open files
that have conflicting advisory locks from HP-UX processes.
You must change the map share modes setting in smb.conf to yes to translate open mode
locks to HP-UX advisory locks. The default setting of map share modes is no.
Performance Tuning using Change Notify
This section describes performance tuning using the Change Notify feature and internationalization.
The Samba Server supports a new feature called Change Notify. Change Notify provides the
ability for a client to request notification from the server when changes occur to files or
subdirectories below a directory on a mapped file share. When a file or directory which is
contained within the specified directory is modified, the server notifies the client. The purpose
of this feature is to keep the client screen display up-to-date in Windows Explorer. The result: if
a file you are looking at in Windows Explorer is changed while you are looking at it, you will
see the changes on the screen almost immediately.
The only way to implement this feature in Samba is to periodically scan through every file and
subdirectory below the directory in question and check for changes made since the last scan.
This is a resource intensive operation which has the potential to affect the performance of Samba
as well as other applications running on the system. Two major factors affect how resource
intensive a scan is: the number of directories having a Change Notify request on them, and the
size of those directories. If you have many clients running Windows Explorer (or other file
browsers) or if you have directories on shares with a large number of files and/or subdirectories,
each scan cycle might be very CPU intensive.
To counteract the possible performance impact, you can control how often Samba scans for
changes in the directories it has been requested to monitor. The parameter that controls how
often Samba scans for changes is Change Notify Timeout. The parameter value represents the
number of seconds between the start of each scanning cycle. The default value is 60. So, if your
system takes 55 seconds to complete the scan of all the directories with Change Notify requests, it
would be under a heavy load at nearly all times.You can increase the Change Notify Timeout value
to a larger number to decrease how often these Change Notify directory scans are done. The trade
off is that your clients will take longer to see that changes were made in the directories that they
have placed Change Notify requests on. You will have to decide what the right trade-off is:
performance loss or slow updates to client file browsers.
Special Concerns when Using HP CIFS Server on a Network File System (NFS) or a
Clustered File System (CFS)
Both NFS and CFS provide file system access to unique file storage from multiple systems.
However, controlling access to files, particularly files open for write access, from multiple systems
Other Samba Configuration Issues 41