Linux operating systems
IBM Tivoli Storage Manager, Version 7.1

Linux: Suggested minimum values for kernel parameters on Linux

Ensure that the values for kernel parameters are sufficient to prevent operational problems from occurring when running the Tivoli® Storage Manager server.

About this task

The following table contains the suggested minimum values for running DB2® on your system. To run Tivoli Storage Manager with DB2, the values might need to be increased above the minimum values specified here. In addition to implementing the suggestions in this table, other changes are required to run both Tivoli Storage Manager and DB2. For details, see http://www.ibm.com/support/docview.wss?uid=swg27015156.

Parameter Description Preferred value
kernel.shmmni See note.

The maximum number of segments

256 × size of RAM in GB
kernel.shmmax See note.

The maximum size of a shared memory segment (bytes)

size of RAM in bytes
kernel.shmall See note.

The maximum allocation of shared memory pages (pages)

2 × size of RAM in bytes (setting is in 4 KB pages)
kernel.sem (SEMMNI) See note.

The maximum number of arrays

256 × size of RAM in GB
kernel.sem (SEMMSL) See note.

The maximum semaphores per array

250
kernel.sem (SEMMNS) See note.

The maximum semaphores per system

256,000
kernel.sem (SEMOPM) See note.

The maximum operations per semaphore call

32
kernel.msgmni See note.

The maximum number of system-wide message queues

1024 × size of RAM in GB
kernel.msgmax See note

The maximum size of messages (bytes)

65,536
kernel.msgmnb See note.

The default maximum size of queue (bytes)

65,536
kernel.randomize_va_space The kernel.randomize_va_space parameter configures the kernels use of memory ASLR. When you set the value to 0, kernel.randomize_va_space=0, it disables ASLR. DB2 data servers rely on fixed addresses for certain shared memory objects, and the ASLR can cause errors for some activities. To learn more details about the Linux ASLR and DB2, see the technote at: http://www.ibm.com/support/docview.wss?uid=swg21365583. 0
vm.swappiness The vm.swappiness parameter defines whether the kernel can swap application memory out of physical random access memory (RAM). For more information about kernel parameters, see the http://pic.dhe.ibm.com/infocenter/db2luw/v10r5. 0
vm.overcommit_memory The vm.overcommit_memory parameter influences how much virtual memory the kernel can permit to be allocated. For more information about kernel parameters, see the http://pic.dhe.ibm.com/infocenter/db2luw/v10r5. 0
Note: For Linux, DB2 automatically increases interprocess communication (IPC) kernel parameter values to the preferred settings.


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