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This article mainly introduces "how to solve the problem that the database cannot be started after modifying the memory configuration under rac". In the daily operation, it is believed that many people have doubts about how to solve the problem that the database cannot be started after modifying the memory configuration under rac. The editor consulted all kinds of materials and sorted out a simple and useful method of operation. Hope to answer the question "how to solve the problem that the database cannot be started after modifying the memory configuration under rac" is helpful! Next, please follow the editor to study!

problem

Today, I found that the rac server I built has 128 gigabytes of memory, while the sga only has 4G PGA and only 4G, so I need to set it a little larger. Since there are no other applications on these two servers except the database, I allocated 80g to sga and 10G to pga. It is strange that the following error occurred when restarting the database:

Solve

At first, it was suspected that the problem was caused by the unreleased memory segment. After checking through ipcs-a, it was found that there was no unreleased phenomenon. After investigation, it was found that the / dev/shm configuration under linux was too small, because the size of / dev/shm was at least greater than or equal to the size of SGA, so the size of / dev/shm was modified to 90g:

Then re-mount / dev/shm. The modification has not been completed here, and the / etc/sysctl.conf file needs to be modified:

Where kernel.shmmax = 85899345920 Kernel.shmall = 41943040, the values here are not written casually, but calculated.

For example, in my SGA=80G, then kernel.shmmax = 80,1024,1024,1024. After the modification is completed, execute sysctl-p to make the modified value take effect, and then startup is successful.

At this point, the study on "how to solve the problem that the database cannot be started after modifying the memory configuration under rac" is over. I hope to be able to solve everyone's doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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