HP CIFS Server Administrator's Guide (5900-1282, April 2011)

12 HP-UX Configuration for HP CIFS
This chapter describes HP-UX tuning procedures for the HP CIFS Server. It contains the following
sections:
• HP CIFS Process Model
• TDB Memory Map for HP CIFS Server
• Overview of Kernel Configuration Parameters
• Configuring Kernel Parameters for HP CIFS
The following information should be considered as general guidelines and not a rigid formula to
determine the resource requirements of a HP CIFS server running on HP-UX 11i v2. Each customer
configuration is unique and on-line tools should be used while the system is running its normal load
to ascertain the requirements of each system.
HP CIFS Process Model
The SMB daemon process, smbd, handles all SMB requests from a client. One such process is
launched for each connected client. Each SMBD process handles one and only one client. Therefore,
if there are 2048 connected clients, there will be 2048 SMBD processes. Such a large number of
processes will demand system resources, requiring adjustment of certain kernel configuration
parameters. It will also deplete memory, disc and swap space resources.
TDB Memory-Mapped Access for HP CIFS Server
Fixed Size Memory Map Support on HP-UX 11i v2 PA and 11i v3 PA Systems
HP CIFS Server A.02.03 and A.03.01a support the fixed size memory map for memory-mapped
access of the locking.tdb file on HP-UX 11i v2 PA and 111i v3 PA systems. HP CIFS Server
can access the Trivial DataBase (TDB) files using memory-mapped access with a pre-determined
size that is sufficient to accommodate the growth of TDB files, so that the risk of data corruption
due to expanding and remapping the memory-mapped files can be avoided. To provide balance
between performance and address space utilization, the fixed size memory map feature is supported
only on locking.tdb.
The smb.conf use mmap parameter controls whether or not the memory map feature is enabled.
The fixed mmap size parameter is used to configure the fixed memory size if the memory map
feature is enabled. See the “Configuration Parameters” section for details.
Configuration Parameters
The following is a list of the global parameters in smb.conf used to support the fixed size memory
map feature:
• use mmap
It is a boolean parameter that controls whether the memory map functionality is enabled or
disabled on the HP CIFS Server. The default setting for this parameter is yes.
• fixed mmap size
This integer variable specifies the fixed memory size for memory-mapped access. The default
value is 16MB. This means that a 16MB contiguous address space is reserved when the file
is first opened and no expansion is allowed. HP recommends that the value of fixed mmap
size should be set to a multiple of the TDB page size. The TDB page size is 8192 bytes.
In the most cases, you should not need to change the default values of the use mmap and fixed
mmap size parameters.
HP CIFS Process Model 151