The following tables list the required MINIMUM values according to the oracle documentation.
| Parameter name in /etc/sysctl.conf | Description | MINIMUM value |
| kernel.sem | “semmsl semmns semopm semmni” | |
| kernel.sem:semmsl | total semaphores for each set | 250 |
| kernel.sem:semmns | total number of semaphores systemwide | 32000 |
| kernel.sem:semopm | Maximum number of operations for semop call | 100 |
| kernel.sem:semmni | total semaphore sets | 128 |
| kernel.shmall | total number of shared memory pages that can be used system wide | 2097152 |
| kernel.shmmax | the maximum size of a single shared memory segment in bytes that a linux process can allocate | Either 4 GB – 1 byte, or half the size of physical memory (in bytes), whichever is lower. Default: 536870912 |
| kernel.shmmni | system wide number of shared memory segments | 4096 |
| fs.file-max | maximum number of open files system-wide | 6815744 |
| fs.aio-max-nr | concurrent outstanding i/o requests | 1048576 |
| net.ip_local_port_range | minimum and maximum ports for use | Minimum: 9000 Maximum: 65500 |
| net.rmem_default | the default size in bytes of the receive buffer | 262144 |
| net.rmem_max | the maximum size in bytes of the receive buffer | 4194304 |
| net.wmem_default | the default size in bytes of the send buffer | 262144 |
| net.wmem_max | the maximum size in bytes of the send buffer | 1048576 |
| Shell Limits for Oracle User in /etc/security/limit.conf | Description | Hard Limit |
| nofile | number of open files | 65536 |
| nproc | number of processes | 16384 |
| stack | stack size in kb | 10240 |
/dev/shm file systemlargest value of MEMORY_MAX_TARGET or MEMORY_TARGET of all instances
Calculate the required values
The following table shows calculation formulas for setting the required kernel parameters for running oracle 11g release 2 on Linux.
| Parameter name in /etc/sysctl.conf | Description | MINIMUM value | Calculation |
| kernel.sem | “semmsl semmns semopm semmni” | ||
| kernel.sem:semmsl | total semaphores for each set | 256 | set fixed to 256 |
| kernel.sem:semmns | total number of semaphores systemwide | 32000 | 2 * sum (process parameters of all database instances on the system) + overhead for background processes + system and other application requirements |
| kernel.sem:semopm | Maximum number of operations for semop call | 100 | set fixed to 100 |
| kernel.sem:semmni | total semaphore sets | 128 | semmns divided by semmsl, rounded UP to nearest multiple to 1024 |
| kernel.shmall | total number of shared memory pages that can be used system wide | 2097152 | ceil(shmmax/PAGE_SIZE). (PAGE_SIZE is usually 4096 bytes unless Big/Huge Pages used) get PAGESIZE by doing: “getconf PAGESIZE” |
| kernel.shmmax | the maximum size of a single shared memory segment in bytes that a linux process can allocate | Either 4 GB – 1 byte, or half the size of physical memory (in bytes), whichever is lower. Default: 536870912 | largest value of SGA_MAX_SIZE, SGA_TARGET,MEMORY_MAX_SIZE or MEMORY_TARGET of all instances |
| kernel.shmmni | system wide number of shared memory segments | 4096 | set fixed to 4096…did not find any formula |
| fs.file-max | maximum number of open files system-wide | 6815744 | >= 6815744 (dont know why this large….but should be enough for most databases) |
| fs.aio-max-nr | concurrent outstanding i/o requests | 1048576 | no adjustment; set fix to 1048576 |
| net.ip_local_port_range | minimum and maximum ports for use | Minimum: 9000 Maximum: 65500 | no adjustment, fixed |
| net.rmem_default | the default size in bytes of the receive buffer | 262144 | >= 262144 |
| net.rmem_max | the maximum size in bytes of the receive buffer | 4194304 | >= 4194304 |
| net.wmem_default | the default size in bytes of the send buffer | 262144 | >= 262144 |
| net.wmem_max | the maximum size in bytes of the send buffer | 1048576 | >= 1048576 |
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