1、数据库启动报错： ORA-27102: out of memory
SQL> startup pfile='/db/oracle/init.ora';
ORA-27102: out of memory
Linux-x86_64 Error: 28: No space left on device
Additional information: -268435456
Additional information: 1
2、内存不足？查看操作系统内存：
$ free -h
total used free shared buffers cached
Mem: 252G 23G 228G 441M 389M 18G
-/+ buffers/cache: 4.5G 247G
Swap: 63G 0B 63G
free:剩余228G，不应该啊。
第一反应什么参数有问题？
sga_max_target=80G
sga_target=70G
没毛病。。。
3、查看操作系统参数：
cat /etc/sysctl.conf
#kernel.shmall = 4294967296
#kernel.shmmni = 4096
#kernel.sem = 25032000100128
#net.ipv4.ip_local_port_range = 900065500
#net.core.wmem_default = 8388608
#net.core.rmem_default = 8388608
#net.core.rmem_max = 16777216
#net.core.wmem_max = 16777216
#fs.aio-max-nr = 3145728
#kernel.shmall = 4294967296
#kernel.shmall = 4294967296
#fs.aio-max-nr = 1048576
#fs.file-max = 6815744
#kernel.shmall = 2097152
#kernel.shmmax = 4294967295
#kernel.shmmni = 4096
#kernel.sem = 250 32000 100 128
#net.ipv4.ip_local_port_range = 9000 65500
#net.core.rmem_default = 262144
#net.core.rmem_max = 4194304
#net.core.wmem_default = 262144
#net.core.wmem_max = 1048576
#net.ipv4.ipfrag_high_thresh = 16777216
#net.ipv4.ipfrag_low_thresh = 15728640
kernel.shmall 发现写了四次，而生效的参数是 kernel.shmall = 2097152
删掉重复的参数，保留 kernel.shmall = 4294967296 ，sysctl -p 使参数生效。
重启数据库解决！