增加/dev/shm大小

Oracle 11g无法启动，报错：

    ORA-00845: MEMORY_TARGET not supported on this system  

网上查说是Oracle SGA设置的比/dev/shm空间大时就会报这个错。


如何修改/dev/shm大小?

/dev/shm在/etc/fstab中挂载，对应tmpfs，实际使用的是内存的空间。默认情况下，/dev/shm为物理内存大小的一半。因而，调整/dev/shm大小有两种方式：

1. 加大Linux的物理内存

2. 在/etc/fstab中明确指定/dev/shm的挂载sizes大小参数，具体配置见下面链接：


Linux下安装Oralce11g 时/dev/shm 大小的更改

http://space.itpub.net/35489/viewspace-671686


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[root@centos-fuwenchao mntsda3]# df -h /dev/shm
Filesystem            Size  Used Avail Use% Mounted on
tmpfs                 935M  228K  935M   1% /dev/shm

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[root@centos-fuwenchao mntsda3]# vi /etc/fstab
      1
      2 #
      3 # /etc/fstab
      4 # Created by anaconda on Fri Nov  1 21:18:42 2013
      5 #
      6 # Accessible filesystems, by reference, are maintained under '/dev/disk'
      7 # See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
      8 #
      9 UUID=8e319772-a274-4031-a53f-1178b3ab4de6 /                       ext4    defaults        1 1
     10 UUID=ad4de750-9575-4040-a403-08c0642f0f2c swap                    swap    defaults        0 0
     11 tmpfs                   /dev/shm                tmpfs   defaults        0 0
     12 devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
     13 sysfs                   /sys                    sysfs   defaults        0 0
     14 proc                    /proc                   proc    defaults        0 0

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[root@centos-fuwenchao mntsda3]# cp /etc/fstab /etc/fstab.20140218
[root@centos-fuwenchao mntsda3]# vi /etc/fstab
      1
      2 #
      3 # /etc/fstab
      4 # Created by anaconda on Fri Nov  1 21:18:42 2013
      5 #
      6 # Accessible filesystems, by reference, are maintained under '/dev/disk'
      7 # See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
      8 #
      9 UUID=8e319772-a274-4031-a53f-1178b3ab4de6 /                       ext4    defaults        1 1
     10 UUID=ad4de750-9575-4040-a403-08c0642f0f2c swap                    swap    defaults        0 0
     11 tmpfs                   /dev/shm                tmpfs   defaults,size=1024M        0 0
     12 devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
     13 sysfs                   /sys                    sysfs   defaults        0 0
     14 proc                    /proc                   proc    defaults        0 0

重新挂载
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[root@centos-fuwenchao mntsda3]# mount -o remount /dev/shm
[root@centos-fuwenchao mntsda3]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda1             9.7G  4.6G  4.7G  50% /
tmpfs                 1.0G  228K  1.0G   1% /dev/shm
/dev/sr0              4.1G  4.1G     0 100% /media/CentOS_6.4_Final
/dev/sda3              38G  176M   36G   1% /mnt/mntsda3