The Unix MediaAgent/iDataAgent uses the operating system's kernel resources, such as shared memory, semaphores, etc., to perform data protection and recovery operations and facilitate inter-process communications and stream management. If you are using an earlier version of the operating system, you can optimize the usage of these resources by setting the kernel parameter values. In addition to maintaining the data in memory, the kernel significantly reduces disk input/output (I/O) activity.
The requirements specified for the resources needed by the CommCell components do not take into consideration any additional resources needed by any other application. Therefore, systems that interact with an application (e.g., Oracle) may require additional resources. These items should be (or should have been) administered by the appropriate application administrator. If you have previously tuned your kernel parameters to the levels that meet your application needs, continue to use the identified values. However, if you do change any kernel settings, make sure to restart the system in order to activate the new settings.
The following table displays the possible range of values for each parameter:
| If "*" appears
after the parameter name, this indicates that you can increment the
value of the parameter based on the number of desired streams by using
the formula parameter value = 64 * number of desired streams as long as the "high-end" value of the range for the parameter is not exceeded. |
| Parameters | Description | Possible Range of Values |
| SEMMNI* | Defines the maximum number of semaphore sets in the entire system. | 1 – 65535 |
| SEMMAP | Defines the maximum number of semaphore map entries. | 1 – 65535 (SEMMNI + 2) |
| SEMMNS* | Defines the maximum semaphores in the system | 1 – 2147483647 [MAXINT] (Default value 128 is too low.) |
| SEMVMX | Defines the maximum value of a semaphore | 32768 |
| SHMMNI* | Defines the maximum number of shared memory segments in the entire system | 1 – 2147483647 [MAXINT] |
| SHMMAX | Defines the maximum allowable size of one shared memory segment | 0 – 4294967295 (Available physical memory); recommended value is 2147483648 |
| SHMSEG* | Defines the maximum number of shared memory segments that one process can attach | 0 - 32767 |
| SEMMNU | Defines the maximum number of System V IPC system-wide processes that can have "undo" operations pending at any given time. | 1 - (nproc-4) [256]; preferred value: 1024 |
Use the following steps to modify the kernel parameters with System Administrator Menu (SAM) for HP-UX File System:
| 1. | From the unix prompt, enter the command to open the System Administrator Menu (SAM). | #sam |
| 2. | In the SAM utility window, double-click the Kernel Configuration icon. | |
| 3. | Double-click the Configurable Parameters icon. SAM will display a screen containing a list of configurable parameters, including current and pending values. | |
| 4. | Double-click on the parameter you wish to change. | |
| 5. | Click New Formula/Value option and type the recommended value. | |
| 6. | Click OK. | |
| 7. | Restart the computer to allow the changes to take effect. |
System Management Homepage (SMH) is the new tool introduced to manage HP-UX. Use the following steps to modify the kernel parameters using System Management Homepage (SMH) since the System Administration Manager (SAM) is deprecated in the current releases of HP-UX:
| 1. | From the unix prompt, enter the command to open the System Management Homepage (SMH) window. |
#smh |
| 2. | In the SMH Text User Interface, select k -Kernel Configuration and press Enter. |
DISPLAY variable is not set. Starting the Text User Interface. Please wait...HP-UX System Management Homepage (Text User Interface) SMH ---------------------------------------------------------- a - Auditing and Security c - Auditing and Security Attributes Configuration(new) d - Peripheral Devices e - Resource Management f - Disks and File Systems g - Display k - Kernel Configuration l - Printers and Plotters(new) m - Event Monitoring Service n - Networking and Communications p - Printers and Plotters s - Software Management u - Accounts for Users and Groups ---------------------------------------------------------- x-Exit smh w-WebLaunch 1-Help ENTER-Launch Functional Area v-SAM Log Viewer |
| 3. | Select the t - Tunables to view a list of configurable parameters, including current and pending values and press Enter. |
SMH->Kernel Configuration ---------------------------------------------------------- t - Tunables View or modify kernel tunables m - Modules View or modify kernel modules and drivers a - Alarms View or modify alarms for kernel tunables l - Log Viewer View the changes made to kernel tunables or modules u - Usage View usage of kernel tunables c - Manage Configuration View the options available to manage configuration b - Restore Previous Boot Values Restores Previous Boot Values for Tunable <-----------------------------------------------------------------------> x-Exit smh ENTER-Select ESC-Back 1-Help |
| 4. | Select the parameter you wish to change and press Enter. For Example, select semmni parameter. |
SMH->Kernel Configuration->Tunables (All) ---------------------------------------------------------------------------- Tunable Tuning Current Next Boot Default Usage Module Capability Value Value Value ===================================================================== semaem Static 16384 16384 16384 - pm_usync semmni Static 2048 2048 2048 1.4% pm_usync semmns Static 4096 4096 4096 3.7% pm_usync semmnu Static 256 256 256 - pm_usync semmsl Dynamic 2048 2048 2048 - pm_usync semume Static 100 100 100 - pm_usync semvmx Static 32767 32767 32767 - pm_usync shmmax Dynamic 1073741824 1073741824 1073741824 3.1% vm_asi shmmni Dynamic 400 400 400 2.2% vm_asi shmseg Dynamic 300 300 300 - vm_asi --------------------------------------------------------------------- x-Exit smh ESC-Back p-Pending b-Restore Previous Boot Values 2-kctune Manpage /-Search ENTER-Details m-Modify d-Dynamic 1-Help 3-Tunable Manpage |
| 5 |
Press m to modify the selected parameter.
Use the following formula to calculate the value for the parameter: parameter value = current value + (64 * number of desired streams)
|
SMH->Kernel Configuration->Tunables (All)->Details Details : semmni --------------------------------------------------------------------------------- Tunable semmni ============================================================================== Description Maximum number of semaphore sets on the system Dynamic no Subsystem pm_usync Default Value 2048 Current Value 2048 Planned Value 2048 Last Boot Value 2048 Constraints semmni >= 2 Constraints semmni <= 32767 Constraints semmni <= semmns Auto Tuning Not Supported Current Usage 28 ----------------------------------------------------------------------------------x-Exit smh m-Modify ESC-Back 1-Tunable Help |
| 6. |
|
SMH->Kernel Configuration->Tunables (All)->Details->Modify ------------------------------------------------------------------------ Tunable semmni Description Maximum number of semaphore sets on the system Module pm_usync Current Value 2048 [Default] Value at Next Boot 2048 [Default] Value at Last Boot 2048 Default Value 2048 Constraints semmni >= 2 semmni <= 32767 semmni <= semmns Can Change At Next Boot Only NOTE: If the new Value is specified as Default, the next boot value will be default value for the tunable as reccomended by HP. However, if the tunable is being autotuned then the value assigned will be determined dynamically by kernel during run-time. New setting[Expression/Value]: ___________________ New setting (evaluated): ___________________ [ Recalculate ] Back up the current configuration before applying change: (X) Yes ( ) No Reason for change : _______________________________________ [ Modify ] [ Preview ] [ Cancel ] ------------------------------------------------------------------------ |
| 7. | A Confirmation window will be displayed warning you that the requested changes have been saved and will take effect at next boot. Press Enter to continue. |
SMH->Kernel Configuration->Tunables (All)->Details->Modify ---------------------------------------------------------------------------------- mount: ignoring incomplete/incorrect entry for /dev/dsk/c0t0d0 in /etc/fstab NOTE: The requested changes could not be applied to the currently running system, for the following reasons: - The tunable 'semmni' cannot be changed without a reboot. * The requested changes have been saved, and will take effect at next boot. Tunable Value Expression semmni (now) 2048 Default (next boot) 2048 2048 mount: ignoring incomplete/incorrect entry for /dev/dsk/c0t0d0 in /etc/fstab Command Successful press Enter Key to continue |
| 8. | Restart the computer. |
The following table displays the possible range of values for each parameter:
| If "*" appears
after the parameter name, this indicates that you can increment the
value of the parameter based on the number of desired streams by using
the formula parameter value = 64 * number of desired streams as long as the "high-end" value of the range for the parameter is not exceeded. |
| Parameters | Description | Possible Range of Values |
| SEMMSL* | Defines the minimum recommended semaphore value. | 1 – 2147483647 [MAXINT] |
| SEMMNS* | Defines the maximum semaphores in the system. | 1 – 2147483647 [MAXINT] |
| SEMOPM | Defines the maximum number of operations for each semaphore call. | 100 |
| SEMMNI* | Defines the maximum number of semaphore sets in the entire system. | 1 – 65535 |
| SHMMNI* | Defines the maximum number of shared memory segments in the entire system. | 1 – 2147483647 [MAXINT] |
| SHMMAX | Defines the maximum allowable size of one shared memory segment. | 0 – 2147483648 [2 GB] (the high-end value is the recommended value) |
| SHMALL | Defines the maximum total shared memory system-wide. | 2097152 |
Use the following steps to modify the kernel parameters:
| 1. | From the unix prompt, log on to the client as root. | |
| 2. | Navigate to the /proc/sys/kernel. | cd /proc/sys/kernel |
| 3. |
View the current values of the parameters in the sem
file. For example, view the values of all semaphore parameters. The output provides the current value for the following parameters in the order listed: SEMMSL, SEMMNS, SEMOPM, and SEMMNI. |
Example: cat sem 250 32000 32 128 In this example, SEMMSL=250, SEMMNS=32000, SEMOPM=32, and SEMMNI=128 |
| 4. |
Modify the required parameter. For example, modify the semmns parameter.
Use the following formula to calculate the value for the parameter: parameter value = current value + (64 * number of desired streams)
|
sysctl -w kernel.<parameter>="value" For example: sysctl -w kernel.semmns="2147483647" |
| 5. | Restart the computer to allow the changes to take effect. |
On a redhat linux computer, you can permanently modify the parameters using the following steps:
| 1. | From the unix prompt, log on to the client as root. | |
| 2. | Open the /etc/sysctl.conf file. | vi /etc/sysctl.conf |
| 3. |
Modify the required parameters. For example, modify the sem parameters.
Use the following formula to calculate the value for the parameter: parameter value = current value + (64 * number of desired streams)
|
sysctl -w
kernel.<parameter>="value1 value2 value3 value4". For Example: sysctl -w kernel.sem="4096 512000 1600 9005"
|
| 3. | Save the sysctl.conf file. |
Press the Esc key. Type :wq |
| 4. | Run the command to allow the changes to take effect. | sysctl -p |
The File System iDataAgent uses the operating system's kernel resources, such as shared memory, semaphores, etc., to perform backup and restore operations. In order to run the backup and restore operations efficiently, you need to ensure that these kernel parameter settings are sufficient for the specific environment.
By default, the kernel parameters are automatically set during the installation of the Macintosh File System iDataAgent . However, you can also modify the parameters at a later point in time if needed.
The following table displays the recommended values for each kernel parameter. Note that the requirements specified for the resources needed by the CommCell components do not take into consideration any additional resources needed by any other application. Therefore, systems that interact with an application (e.g., Oracle) may require additional resources. These items should be (or should have been) administered by the appropriate application administrator.
| If "*" appears
after the parameter name, this indicates that you can increment the
value of the parameter based on the number of desired streams by using
the formula parameter value = 64 * number of desired streams as long as the "high-end" value of the range for the parameter is not exceeded. |
| Parameters | Description | Possible Range of Values |
| SEMMNI* | Defines the maximum number of semaphore sets in the entire system. | 1 – 65535 |
| SEMMNS* | Defines the maximum semaphores in the system. | 1 – 2147483647 [MAXINT] |
| SEMMSL* | Defines the minimum recommended semaphore value. | 1 – 2147483647 [MAXINT] |
| SHMALL | Defines the maximum total shared memory system-wide. | shmmax/hw_pagesize |
| SHMMIN | Defines the minimum allowable size of a single shared memory segment | 1 |
| SHMMNI* | Defines the maximum number of shared memory segments in the entire system. | 1 – 2147483647 [MAXINT] |
| SHMMAX | Defines the maximum allowable size of one shared memory segment. | 0 – 2147483648 [2 GB] (the high-end value is the recom |
| SHMSEG* | Defines the maximum number of shared memory segments that one process can attach. | 0 - 32767 |
Use the following steps to modify the kernel parameters on Macintosh clients:
| 1. | Log in to the client as root. | |
| 2. | Ensure that no jobs are running on the client. | |
| 3. | Navigate to the /etc directory. | |
| 4. | Edit the required parameter in the
sysctl.conf
file. For example, set the value for semmni
parameter to 55680 If the sysctl.conf file does not exist, edit the /etc/rc script instead (in this case, the kernel parameter configurations are located under either the Start BootCache section or System Tuning section of the /etc/rc script). Use the following formula to calculate the value for the parameters marked with * in the above table: parameter value = 64 * number of desired streams as long as the high-end value of the range for the parameter is not exceeded. |
Example: kern.sysv.shmmni=12288 |
| 5. | Save the sysctl.conf file or the rc script. | |
| 6. | Restart the computer to allow the changes to take effect. |
By default, the kernel parameters are set during the installation. However, you can also modify the parameters at a later point in time if needed.
The following table displays the possible range of values for each parameter for Solaris 9 and below:
| If "*" appears
after the parameter name, this indicates that you can increment the
value of the parameter based on the number of desired streams by using
the formula parameter value = 64 * number of desired streams as long as the "high-end" value of the range for the parameter is not exceeded. |
| Parameters | Description | Possible Range of Values |
| SEMMNI* | Defines the maximum number of semaphore sets in the entire system. | 1 – 65535 (unsigned short) |
| SEMMNS* | Defines the maximum semaphores in the system. | 1 – MAXINT MAXINT = 0x7fffffff (2147483647) |
| SEMMSL* | Defines the minimum recommended semaphore value. | 1 – MAXINT MAXINT = 0x7fffffff (2147483647) |
| SHMMIN | Defines the minimum allowable size of a single shared memory segment. | 0 (Physical Ram) 1 (It is recommended not to change the current value if set. If no value exists, set it to 1.) |
| SHMMNI* | Defines the maximum number of shared memory segments in the entire system. | 0 – MAXINT MAXINT = 0x7fffffff (2147483647) |
| SHMMAX | Defines the maximum allowable size of one shared memory segment. | 0 - MAXINT3264
MAXINT3264 = MAXINT (if 32-bit) or 0x7fffffffffffffff (if 64-bit) (If the current value is less than 4199304, then set it to 4199304.) |
| SHMSEG* | Defines the maximum number of shared memory segments that one process can attach. | 0 - 32767 (signed short) |
| SEMINFO_SEMMNU | Defines the total number of undo structures supported by the System V semaphore system. | 1024 |
Use the following steps to modify the kernel parameters for Solaris 9 and below:
| 1. | From the unix prompt, create a backup copy of the /etc/system file. | cp /etc/system /etc/system.copy |
| 2. | Open the /etc/system file. | vi /etc/system |
| 3. | Change the desired parameter value as per the range given
in the above table.
For example, set the value for semmni parameter to 55680 Use the following formula to calculate the value for the parameter: parameter value = current value + (64 * number of desired streams)
|
Example: set semsys:seminfo_semmni=55680 |
| 4. | Save the /etc/system file. |
|
| 5. | Restart the computer to allow the changes to take effect. |
The following table displays the possible range of values for each parameter for Solaris 10 and above:
| project.max-shm-memory | Defines the total amount of shared memory allowed for a project. | [Default = 25% of the physical memory]
It is recommended not to set this value. However, if you have to set the control to accommodate other resource consumers, ensure that the value is not less than 2MB = [2097152]. |
| project.max-shm-ids* | Defines the maximum number of shared memory IDs allowed for a project | 16777216 [Default = 128] |
| project.max-sem-ids* | Defines the maximum number of semaphores allowed for a project | 16777216 [Default = 128] |
For Solaris 10 and above, you can use any of the following commands to modify the kernel parameters:
Use the following steps to modify the kernel parameters in Solaris 10 and above versions using the projmod command:
| 1. | From the unix prompt, type the
projmod command. projmod [-n] [-f filename] [-p projid [-o]] [-c comment] [-a|-s|-r] [-U user [,user...]] [-G group [,group...]] [[-K name[=value[,value...]...]]] [-I new_projectname] project |
Example: projmod -s -K "project.xxx" user.root |
| 2. | Change the desired parameter value as per the range given
in the above table. For example, set the value for project.max-shm-ids parameter Use the following formula to calculate the value for the parameter: parameter value = current value + (64 * number of desired streams)
|
Example: projmod -s -K "project.max-shm-ids=(priv,1280,deny)" user.root |
| 3. | Restart the computer to allow the changes to take effect. |
Use the following steps to modify the kernel parameters in Solaris 10 and above versions using the prctl command:
| 1. | From the unix prompt, type the
prctl command. prctl [-P] [-t[basic| privileged| system]] [-n name] [-v value] [-e| d action] [-p pid] [-i idtype] id... |
Example: projmod -n project.xxx -v xxx -r -i project user.root |
| 2. | Change the desired parameter value as per the range given
in the above table.
For example, set the value for project.max-shm-ids parameter Use the following formula to calculate the value for the parameter: parameter value = current value + (64 * number of desired streams)
|
Example: prctl -n project.max-shm-ids -v 1280 -r -i project user.root Output: project: 1: user.root project.max-shm-ids privileged 1280 - deny - project.max-shm-ids system 16777216 max deny – |
| 3. | Restart the computer to allow the changes to take effect. |
The following table displays the possible range of values for each parameter:
| If "*" appears
after the parameter name, this indicates that you can increment the
value of the parameter based on the number of desired streams by using
the formula parameter value = 64 * number of desired streams as long as the "high-end" value of the range for the parameter is not exceeded. |
| Parameters | Description | Possible Range of Values |
| SEMMNI* | Defines the maximum number of semaphore sets in the entire system. | 1 – 65535 |
| SEMMSL* | Defines the minimum recommended semaphore value | 1 – 2147483647 [MAXINT] |
| SEMOPM | Defines the maximum number of operations for each semaphore call | 100 |
| SEMVMX | Defines the maximum value of a semaphore | 32767 |
| SEMUME | Defines the maximum number of undo entries per process | 64 |
| SEMAEM | Defines the maximum value for adjustment on exit | 16384 |
| SHMMIN | Defines the minimum allowable size of a single shared memory segment |
0 ( Physical Ram) 1 |
| SHMMNI* | Defines the maximum number of shared memory segments in the entire system | 1 – 2147483647 [MAXINT] |
| SHMMAX | Defines the maximum allowable size of one shared memory segment | 0 – 4294967295 (recommended value is 2147483648) |
| SHMSEG* | Defines the maximum number of shared memory segments that one process can attach | 0 - 32767 |
Use the following steps to modify the kernel parameters:
| 1. | From the unix prompt, create a backup copy of the /etc/sysconfigtab file. |
Example: cp /etc/sysconfigtab /etc/sysconfigtab.copy |
| 2. |
Use the ipcs
command to view the current values of the parameters. You can also view the kernel parameters in sysconfig file using the following commands:
|
Example: ipcs -m -s shm_max=1073741824 shm_mni=1024 shm_min=1 shm_seg=256 sem_mni=128 sem_msl=128 sem_opm=100 sem_ume=64 sem_vmx=32768 sem_aem=16384
sysconfig -s Example: sysconfig -s
|
| 3. |
Modify the required parameter value.
For example, modify the shm_mni parameter. Use the following formula to calculate the value for the parameter: parameter value = current value + (64 * number of desired streams)
|
sysconfig -r
<parameter>="value" Example: sysconfig -r shm_mni="2147483647" |
| 4. | Save the sysconfigtab file. |
Press the Esc key. Type :wq |
| 5. | Restart the computer. |