configuration | Datastage

If you have large parallel jobs (8.1) running in Windows environment then it is worth checking the servers event log. You could find an error related to Nutcracker.exe. An administrator with access right on the server can see the events logs.

Nutcracker error could come up while running very heavy jobs where total cpu utilization is upto or above 90% and server starts using virtual memory. This is just an example of the impact of running large parallel jobs in Windows server. Hence to make the system somewhat full proof following changes can be done in Windows registry. The idea is to tune the TCP/IP buffer, increase the heap size and set the virtual memory to the recommended amount.

To tune TCP/IP settings go to registry editor and check if MaxUserPort and TcpNumConnections keys are present in the TCP/IP buffer and connection registry. Generally they will not be there. TcpNumConnections settings will impact on number of Osh processes.

To change the settings
Go to registry editor
Go to HKEY_LOCAL_MACHINE > SYSTEM > CurrentControlSet > Services > Tcpip > Parameters.
Now on the right pane modify the values:
Value Name: MaxUserPort
Value Type: DWORD
Value data: 65534
More information on MaxUserPort click here.

Value Name: TcpNumConnections
Value Type: DWORD
Value data: 65534
More information on TcpNumConnections click here.

To change the heap size
Go to registry editor and change the non interactive desktop heap size.
Go to HKEY_LOCAL_MACHINE > SYSTEM > CurrentControlSet > Control > Session Manager > SubSystems.
Click on windows on the right pane.
Now edit the ShareSection parameter in the value box
Change the last value from 512 to 1024.

Now what is Desktop heap and why we are changing it?

In windows anything you create as a desktop object has got some amount of memory attached to it which is known as single desktop heap. The desktop heap is responsible for storing user interface objects, for example menus (Start for example) and windows (any new Window). When we run any application which needs to create these kind of interface object it needs space (in general terms, however it does have a process by which it allocates the area.) which goes from Desktop heap. In normal scenarios no one bother about how much Desktop heap has been configured in the system. The interesting thing here is if the application does not require any kind of interface objects it will not allocate the area from heap. The value which we are changing here is related to non interactive desktop which is related to services. So we are allowing more heap size in our environment so that while running services it should not exhaust. If you need more information on Windows heap please click here.

Now the last bit is changing the virtual memory configuration.

Virtual memory can be configured by right clicking on “My Computer” and going to Advance tab’s performance section. Now change the virtual memory to the recommended size. For example if you have 8GB of RAM then recommended size would be 12 GB.

However all above setting can overcome issues related to large jobs but patches recommended for Nutcracker issue should also be installed.

For more information – http://publib.boulder.ibm.com/infocenter/iisinfsv/v8r5/index.jsp?topic=/com.ibm.swg.im.iis.productization.iisinfsv.install.doc/topics/wsisinst_config_pe_win.html

If the parallel engine is installed on a computer that runs Microsoft Windows Server, Standard or Enterprise edition, you can configure the parallel engine for Microsoft Windows Server, 32-bit or 64 bit editions, by editing the Windows Registry and by changing system settings that control available memory. The Windows Registry includes keys that control desktop heap size, swap area size, the number of available TCP connections, and memory management.

1. Before Starting Configuration

Log in to Windows Server as the Administrator.
Start the Registry Editor, In Window Server 2008, open the DOS prompt as Administrator (right click on the dos prompt and select “Run as administrator”. From the DOS prompt, enter regedit

C:Windowssystem32>regedit

Back up the Windows Registry. If you plan to make several changes (for example, to configure the parallel engine), create a single backup before you make all the changes. To backup the registry, From the Registry Editor, select File -> Export and save the registry to a file.

2. Configuring the Windows Registry: Enabling auto-tuning for paged pool size

Enable auto-tuning for the paged pool size. Enabling auto-tuning ensures that sufficient memory is available for paged pools.

The Windows Server kernel allocates memory in pools. These pools are known as the paged pool and the non-paged pool. Performance degradation and server instability might result if the memory for these pools is exhausted. To avoid this situation, you can enable auto-tuning at server startup by editing the PagedPoolSize registry value in the HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSession ManagerMemory Management registry subkey.

2.1 Procedure

(1.) In the Registry Editor, select the following registry subkey:

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSession ManagerMemory Management

(2.) in the right pane of the Registry Editor, right-click PagedPoolSize, and click Modify.
(3.) in the Base area, select Hexadecimal.
(4.) In the Value data field, specify 0 (zero). If 0 is already specified, auto-tuning is enabled, and you do not need to change this value. If you must specify a value other than 0, the value data for SystemPages must be 0.
(5.) Click OK.

3. Configuring the Windows Registry: Enabling auto-tuning for system page size

Enable auto-tuning for the system page size. Enabling auto-tuning ensures that sufficient memory is available for page tables and page table entries.

To support virtual to physical address translation, the Windows operating system uses page tables and page table entries (PTEs). These tables reside in kernel memory. If not enough memory is allocated for the page tables, Windows might fail to create processes, threads, and I/O buffers. Because the parallel engine creates many processes to run a job, jobs will fail at startup or during run time if Windows does not have enough resources to create processes.

You can enable auto-tuning at server startup by editing the SystemPages registry value in the HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSession ManagerMemory Management registry subkey.

3.1 Procedure

(1.) In the Registry Editor, select the following registry subkey:

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSession ManagerMemory Management

(2.) In the right pane of the Registry Editor, right-click SystemPages, and click Modify.
(3.) In the Base area, select Hexadecimal.
(4.) In the Value data field, specify 0 (zero). Typically, specifying 0 for this value provides sufficient memory. If the available PTEs are exhausted, however, you can specify the maximum value, 0XFFFFFFFF. If you must specify a value other than 0, the value data for PagedPoolSize must be 0.
(5.) Click OK.

4 Configuring the Windows registry: Setting the threshold for de-committing memory

Set the threshold for de-committing memory. On computers that have 1 GB or more of RAM, setting the threshold to the suggested value improves memory management.

When Windows frees memory at a specific address, the memory can remain committed, or it can be de-committed and marked as reserved. You can improve memory management on computers that have 1 GB or more of RAM by editing the HeapDeCommitFreeBlockThreshold registry value in the HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSession Manager registry subkey. This registry value specifies the number of contiguous bytes of memory (around the address of the freed memory) above which the block of memory is de-committed.

4.1 Procedure

(1.) In the Registry Editor, select the following registry subkey:

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSession Manager

(2.) Specify the value data for HeapDeCommitFreeBlockThreshold registry value:
(3.) If the registry value does not exist, click Edit > New > DWORD Value, and type the name of the registry value.
(4.) In the right pane of the Registry Editor, right-click the registry value, and click Modify.
(5.) In the Base area, select Hexadecimal.
(6.) In the Value data field, specify 0x000400.
(7.) Click OK.

5 Configuring the Windows registry: Increasing the noninteractive desktop heap size

Increase the noninteractive desktop heap size to ensure that a sufficient number of processes can be created and run concurrently.

DataStage® processes are created in a specific desktop heap. Each process consumes a small amount of memory from the desktop heap. If you expect to run many InfoSphere DataStage jobs concurrently, increase the size of the noninteractive desktop heap to allow more processes to be created and run concurrently.

You increase the size of the noninteractive desktop heap by editing the SharedSection parameter string in the HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSession ManagerSubSystems registry subkey. The SharedSection parameter string is located in the Windows registry value and uses the following format to specify heap size:

SharedSection=xxxx,yyyy,zzzz

Where:

· xxxx specifies the maximum size of the system-wide heap (in kilobytes)
· yyyy specifies the size of each desktop heap
· zzzz specifies the size of the desktop heap that is associated with a noninteractive Windows instance

5.1 Procedure

(1.) In the Registry Editor, select the following registry subkey:

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSession ManagerSubSystems

(2.) In the right pane of the Registry Editor, right-click the Windows registry value, and click Modify.

(3.) In the Value data field, locate the SharedSection parameter string, and change the last SharedSection parameter from 512 to 2048. For example, specify the following values for this parameter:

SharedSection=1024,3072,2048

If you cannot change the size of the desktop heap to 2048, try setting the value to 1024. For example, specify the following values for this parameter:

SharedSection=1024,3072,1024
(4.) Click OK.

6. Configuring the Windows registry: Specifying TCP/IP settings

Specify settings for TCP/IP in the Windows Registry to ensure that the required number of parallel processes can run concurrently.

You specify TCP/IP settings by editing the following registry values in the HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesTcpipParameters registry subkey:

MaxUserPort

Specifies the maximum port number for ephemeral TCP ports.

TcpNumConnections

Specifies the maximum number of concurrent connections that TCP can open. This value significantly affects the number of concurrent osh.exe processes that are allowed. If the value for TcpNumConnections is too low, Windows cannot assign TCP ports to stages in parallel jobs, and the parallel jobs cannot run.

These keys are not added to the registry by default.

6.1 Procedure

(1.) In the Registry Editor, select the following registry subkey:

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesTcpipParameters

(2.) Specify the following registry values: MaxUserPort and TcpNumConnections.

a. If the registry value does not exist, click Edit > New > DWORD Value, and type the name of the registry value.
b. In the right pane of the Registry Editor, right-click the registry value, and click Modify.
c. In the Base area, select Hexadecimal.
d. In the Value data field, specify the following values:
    Registry value name                         Value data                          Valid range
     MaxUserPort                                      65534                                5000 – 65534 (decimal)
    TcpNumConnections                        65534                                 0 – 0xfffffe (65534 decimal)
e. Click OK.

7 Configuring Windows: Changing swap area size

Change the size of the swap area to improve performance.

7.1 Procedure

(1.) Click Start > Control Panel > System.
(2.) In the System Properties window, click the Advanced tab.
(3.) In the Performance area, click Settings.
(4.) In the Performance Options window, select the Advanced tab.
(5.) In the Virtual memory area, click Change.
(6.) In the Virtual Memory window, specify a value for Maximum size. Set this value to be one to one- and-a-half times larger than the value for physical memory.
(7.) Click Set.
(8.) Click OK three times, and then close the Control Panel window.

8. Configuring Windows: Enable Physical Address Extension (PAE)

Enable /PAE switch. Edit the boot.ini file to remove the /3GB switch and, if necessary, add the /PAE switch.

By default, Windows reserves 2 GB of memory for the kernel and 2 GB of memory for user mode programs. When the /3GB switch is specified in the boot.ini file, 3 GB of memory is reserved for user mode programs, and the amount of kernel memory is reduced by 1 GB. This setting results in an insufficient amount of memory for the kernel. To resolve this problem, remove the /3GB switch, if present from boot.ini file(for Windows Server 2000 or 2003).

In addition, on servers that have more than 4 GB of physical memory installed, specify the /PAE switch in the boot.ini file. For Windows 2008 server, use the BCDEDIT.exe tool (see section 11.8.1 below). The /PAE switch specifies physical address extensions that allow a 32-bit processor to access memory that is above the 4 GB limit.

8.1 Procedure

(1.) Click Start > Control Panel > System.
(2.) In the System Properties window, click the Advanced tab.
(3.) In the Startup and Recovery area, click Settings.
(4.) Click Edit to edit the boot.ini file.
(5.) Remove the /3GB switch, if present.
(6.) On servers that have more than 4 GB of physical memory installed, add the /PAE switch to the boot.ini file.
(7.) Save and close the boot.ini file.
(8.) Click OK twice, and then close the Control Panel window.

Note: There is no boot.ini in Windows Server 2008. To enable PAE in Windows 2008 server, use the Boot Configuration Data Editor, BCDEDIT.EXE, which is located in c:windowssystem32 and follow the following steps:

(1.) Open Command Prompt with elevated privileges (Run as Administrator)
(2.) Execute the following command

BCDEDIT /SET PAE ForceEnabl

(3.) To verify, run BCDEDIT without any switch:

BCDEDIT

You should see “PAE ForceEnabl” at the end of the screen.

9 Restart Windows Server

After you make changes to the Windows Registry, restart Windows to apply your changes.

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