memory_target needs larger /dev/shm

今天rac起不来，检查alert发现 /dev/shm is either not mounted or is mounted with available space less than this size
memory_target needs larger /dev/shm
相关错误如下：
[code][root@node2 trace]# more alert_ORASQL2.log
Fri Aug 16 19:50:54 2013
Starting ORACLE instance (
normal)
WARNING: You are trying to use the MEMORY_TARGET feature. This feature requires the /dev/shm file system to be mounted for at least 838860800 bytes. /dev/shm is either not mou
nted or is mounted with available space less than this size. Please fix this so that MEMORY_TARGET can work as expected. Current available is 0 and used is 0 bytes. Ensure tha
t the mount point is /dev/shm for this directory.
memory_target needs larger /dev/shm[/code]
检查磁盘信息，发现/dev/shm未挂载
[code][root@node2 trace]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
ext3 18G 11G 5.9G 65% /
/dev/sda1 ext3 99M 23M 71M 25% /boot[/code]
手工挂载，并在fstab填写相关信息，开机自动挂载
[code][root@node2 trace]# mount -t tmpfs shmfs -o size=1024m /dev/shm
[root@node2 trace]# vim /etc/fstab

tmpfs /dev/shm tmpfs size=1024m 0 0

[root@node2 trace]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
ext3 18G 11G 5.9G 65% /
/dev/sda1 ext3 99M 23M 71M 25% /boot
shmfs tmpfs 1.0G 0 1.0G 0% /dev/shm[/code]