How to Resolve ORA-27106: system pages not available to allocate memory?

Question

I was working well before changing below code.

alter database archivelog;
alter system set sga_max_size = 20480M  scope=spfile;

Currently Error is

ORA-27106: system pages not available to allocate memory 
additional information 6128

Answer 1

Check shmmax kernel parameter and set to recommended value- This parameter defines the maximum size in bytes of a single shared memory segment that a Linux process can allocate in its virtual address space.

Caution - when tying to allocate SGA size bigger than SHMMAX the error below occur. “SGA size con not be greater than maximum shared memory segment size (shmmax value)”

If shm* parameter are set, then look at hugepages (it may be due to insufficient HugePages)

grep -huge /proc/meminfo

and try to free it.