HP CIFS Server 3.0f Administrator's Guide verison A.02.03

13 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 v1 and 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 v1, 11i v2 PA and 11i v3 PA Systems
HP CIFS Server A.02.03 supports the fixed size memory map for memory-mapped access of the
locking.tdb file on HP-UX 11i v1, 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 Parameterssection 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.
NOTE: To modify the value of use mmap or fixed mmap size, you must first stop all of the CIFS Server
processes (smbd, nmbd and winbindd daemons), modify the settings of the parameters, and then restart the
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