installing oracle 11g r2, No space left on device /tmp

[oracle@ora11g database]$ ./runInstaller 
Error in writing to directory /tmp/OraInstall2011-09-17_10-02-06PM. Please ensure that this directory is writable and has atleast 60 MB of disk space. 
Installation cannot continue.
: No space left on device
Starting Oracle Universal Installer...

[oracle@ora11g database]$ df -h /tmp
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda5             3.1G  3.0G     0 100% /
[oracle@ora11g database]$ df
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/sda5              3236704   3069712         0 100% /
/dev/sda2             10908540    158728  10186736   2% /oracle
/dev/sda1               101086     11061     84806  12% /boot
tmpfs                   257760         0    257760   0% /dev/shm
/dev/hdc                107456    107456         0 100% /mnt/cdrom
.host:/               51199120  37617896  13581224  74% /mnt/hgfs

提示/tmp空间不足，查看官方文档，（离不开的百科全书）
The following are the disk space requirements for installing Oracle Database 11g
Release 2 (11.2):
■ At least 1 GB of disk space in the /tmp directory
To determine the amount of disk space available in the /tmp directory, enter the
following command:
# df -h /tmp
If the free disk space available in the /tmp directory is less than what is required,
then complete one of the following steps:
■ Delete unnecessary files from the /tmp directory to meet the disk space
requirement.
■ Set the TMP and TMPDIR environment variables when setting the oracle
user’s environment.
■ Extend the file system that contains the /tmp directory. If necessary, contact
the system administrator for information about extending file systems.

[oracle@ora11g tmp]$ TMP=/oracle/temp
[oracle@ora11g tmp]$ TMPDIR=/oracle/temp
[oracle@ora11g tmp]$ export TMP TMPDIR
[oracle@ora11g tmp]$ cd /mnt/hgfs/Untitled-1/
[oracle@ora11g Untitled-1]$ cd /mnt/hgfs/Untitled-1/linux_11gR2_database/database/
[oracle@ora11g database]$ ./runInstaller 
Starting Oracle Universal Installer...
Checking Temp space: must be greater than 80 MB.   Actual 9947 MB    Passed
Checking swap space: must be greater than 150 MB.   Actual 996 MB    Passed
Checking monitor: must be configured to display at least 256 colors.    Actual 16777216    Passed
Preparing to launch Oracle Universal Installer from /oracle/temp/OraInstall2011-09-17_10-06-26PM. Please wait ...
[oracle@ora11g database]$ 

894M /oracle/temp

note:oracle 11g 安装对/tmp目录的要求从10g的400m,上升为1g，企业版我查看了一下是临时文件占用894M，如果/tmp目录空间不足，需要当前用设置环境变量TMP 和TMPDIR 指定到其它路径，注意区分大小写!