更换ssl证书后，重启Apache失败。
查看Apache的error日志发现：
[Fri May 20 18:07:23 2011] [crit] (28)No space left on device: mod_rewrite: could not create rewrite_log_lock
Configuration Failed
[Fri May 20 18:08:22 2011] [crit] (28)No space left on device: mod_rewrite: could not create rewrite_log_lock
Configuration Failed
[Fri May 20 18:13:50 2011] [crit] (28)No space left on device: mod_rewrite: could not create rewrite_log_lock
Configuration Failed
[Fri May 20 18:13:52 2011] [crit] (28)No space left on device: mod_rewrite: could not create rewrite_log_lock
Configuration Failed
解决方法：
#重新写入一些活动信号量集的信息
ipcs -s | grep apache | perl -e 'while (<stdin>) { @a=split(/\s+/); print `ipcrm sem $a[1]`}'
</stdin>
参考链接：
http://carlosrivero.com/fix-apache―no-space-left-on-device-couldnt-create-accept-lock