Linuxkernel. shmallshemaxshemin

Linuxkernel. shmallshemaxshemin explains the LinuxX86-64 operating system, Oracle10g database, from 8G to 16G, the kernel. after the shmmax parameter is changed to 17179869184 (16G), it is found that as long as the sga_max_size and sga_target parameters are modified to more than 8G, Oracle will... linux kernel. shmall shemax shemin explains Linux X86-64 operating system, Oracle 10G database, from 8G to 16G, the kernel. after the shmmax parameter is changed to 17179869184 (16 GB), it is found that as long as the sga_max_size and sga_target parameters are modified to exceed 8 GB, Oracle will report that the memory is insufficient to start, and check the other two parameters related to the shared memory parameters: kernel. shmall and kernel. shmmni, kernel. the shmall parameter controls the number of pages in the shared memory, kernel. shm The mni parameter controls the total number of shared memory segments. The current parameter value is 4096, which is large enough. The problem should be indicated by the kernel. on shmall, divide the value by 8589934592 (8G) and the result is 2097152. the page size is 4 K. to adjust SGA to a value greater than 8G, we need to increase the kernel. after the shmall parameter is adjusted to 2 times (4194304) of the current value, the sga can be successfully set to 13 GB. For 32-bit systems, one page is 4 kB, that is, 4096 bytes. Kernel. shmall = 2097152 is 2097152*4 k/1024/1024 = 8G, that is, the shared memory is available for a total of 8G above shmmax = 2G 512 32000 100 100>/proc/sys/kernel/sem are SEMMSL (the maximum number of semaphores owned by each user ), SEMMNS (maximum number of system semaphores), SEMOPM (number of calls to the semop system each time), and SEMMNI (maximum number of system semaphores) REDHAT AS4 kernel. for the sem settings, you usually need to set the kernel before installing oracle. sem is the abbreviation of semaphores, view the current setting [oracle @ ebsse oracle] $ cat/proc/sys/kernel/sem250 32000 100 1284 data corresponds to semmsl semmns semopm sem respectively If the PROCESSES parameter settings in the oracle DB initialization parameter file are large, you need to adjust SEMAPHORES to set SEMMSL to the maximum PROCESSES parameter + 10 for each instance on the server. for example, when the maximum PROCESSES parameter is 5000, SEMMSL should be set to 5010. SEMMNS parameter should be set to SEMMSL * SEMMNI, SEMMSL is 5010, SEMMNS parameter should be (5010*128) = 641280. The SEMOPM parameter should be set to the same as the SEMMSL parameter. In this example, set to 5010 to change the current SEMAPHORES parameter settings: [oracle @ ebsse oracle] $ suPassword: [root @ ebsse oracle] # echo "5010 641280 5010 128">/proc/sys/kernel/sem [root @ ebsse oracle] # cat/proc/sys/kernel/sem5010 641280 5010 if you need to enable automatic application, in/etc/sysctl. conf added: kernel. sem = 5010 641280 5010 128