在oracle linux上安装oracle 11g的过程中对于os的共享内存（/dev/shm）还是有一定的要求的，其大小不能小于你分配给oracle使用的内存的大小：
Starting with Oracle Database 11g, the Automatic Memory Management feature
requires more shared memory (/dev/shm)and file descriptors. The size of the shared
memory should be at least the greater of MEMORY_MAX_TARGET and MEMORY_TARGET
for each Oracle instance on the computer. If MEMORY_MAX_TARGET or MEMORY_
TARGET is set to a non zero value, and an incorrect size is assigned to the shared
memory, it will result in an ORA-00845 error at startup. The number of file descriptors
for each Oracle instance should be at least 512*PROCESSES. Also, the limit of
descriptors for each process should be at least 512. If file descriptors are not sized
correctly, you will notice ORA-27123 from various Oracle processes and potentially
Linux Error EMFILE (Too many open files) errors in non-Oracle processes.
于是我悲剧了，发现我初始安装Oracle Linux的时候给的/dev/shm太小了（其实我都忘记自己在哪里设置了这个参数了..）,好吧，只能修改了。
vi /etc/fstab，在其中添加size=4096M，然后mount -o remount /dev/shm就可以了，如下：
tmpfs /dev/shm tmpfs defaults,size=4096M 0 0
[root@gongwenServer srvadmin]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 95G 5.4G 85G 6% /
/dev/sda4 294G 195M 278G 1% /opt
/dev/sda1 190M 12M 169M 7% /boot
tmpfs 4.0G 0 4.0G 0% /dev/shm
好了，ok,rush the way to oracle 11g