在上一篇文章中，说到bdump目录的x权限丢失，导致oracle数据库异常。
下面就来用linux 的strace命令来跟踪一下，当bdump目录的x权限丢失时，sqlplus / as sysdba会有什么样的输出：
strace命令如下，该命令来源于：Using Strace in Linux to Debug Hang Type Problems (Doc ID 1391746.1)
strace -fe verbose=all -e write=all -e read=all -o /u02/app/output7.txt /u02/app/oracle/product/11.2.0.4/db_1/bin/sqlplus / as sysdba
当上面的strace命令执行完毕后，output7.txt的大小为：
[root@rhel63single app]# pwd /u02/app [root@rhel63single app]# du -sh output7.txt 54M output7.txt
在该文件的中，有如下信息：
5774 stat("/u01/app/oracle/diag", {st_mode=S_IFDIR|0775, st_size=4096, ...}) = 0
5774 stat("/u01/app/oracle/diag/rdbms", {st_mode=S_IFDIR|0775, st_size=4096, ...}) = 0
5774 stat("/u01/app/oracle/diag/rdbms/test", {st_mode=S_IFDIR|0750, st_size=4096, ...}) = 0
5774 stat("/u01/app/oracle/diag/rdbms/test/test", {st_mode=S_IFDIR|0750, st_size=4096, ...}) = 0
5774 stat("/u01/app/oracle/diag/rdbms/test/test/trace", {st_mode=S_IFDIR|0650, st_size=49152, ...}) = 0 --->此处说明该bdump目录的权限为650
5774 mkdir("/u01/app/oracle/diag/rdbms/test/test/trace", 0775) = -1 EEXIST (File exists) ----->此处要以755权限新建该bdump目录，只是由于该目录已经存在而建立失败。
而当bdump目录有x权限时，sqlplus / as sysdba的strace跟踪如下：
6451 stat("/u01/app/oracle", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
6451 getrlimit(RLIMIT_NOFILE, {rlim_cur=64*1024, rlim_max=64*1024}) = 0
6451 open("/proc/self/fd/", O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = 5
6451 fcntl(5, F_GETFD) = 0x1 (flags FD_CLOEXEC)
6451 getrlimit(RLIMIT_FSIZE, {rlim_cur=RLIM_INFINITY, rlim_max=RLIM_INFINITY}) = 0
6451 stat("/u01/app/oracle/diag", {st_mode=S_IFDIR|0775, st_size=4096, ...}) = 0
6451 stat("/u01/app/oracle/diag/rdbms", {st_mode=S_IFDIR|0775, st_size=4096, ...}) = 0
6451 stat("/u01/app/oracle/diag/rdbms/test", {st_mode=S_IFDIR|0750, st_size=4096, ...}) = 0
6451 stat("/u01/app/oracle/diag/rdbms/test/test", {st_mode=S_IFDIR|0750, st_size=4096, ...}) = 0
6451 stat("/u01/app/oracle/diag/rdbms/test/test/trace", {st_mode=S_IFDIR|0750, st_size=49152, ...}) = 0 --->该bdump权限是750
6451 stat("/u01/app/oracle/diag/rdbms/test/test/alert", {st_mode=S_IFDIR|0750, st_size=4096, ...}) = 0
6451 stat("/u01/app/oracle/diag/rdbms/test/test/incident", {st_mode=S_IFDIR|0750, st_size=4096, ...}) = 0
6451 stat("/u01/app/oracle/diag/rdbms/test/test/metadata", {st_mode=S_IFDIR|0750, st_size=4096, ...}) = 0
6451 stat("/u01/app/oracle/diag/rdbms/test/test/metadata_pv", {st_mode=S_IFDIR|0750, st_size=4096, ...}) = 0
6451 stat("/u01/app/oracle/diag/rdbms/test/test/metadata_dgif", {st_mode=S_IFDIR|0750, st_size=4096, ...}) = 0
6451 stat("/u01/app/oracle/diag/rdbms/test/test/hm", {st_mode=S_IFDIR|0750, st_size=4096, ...}) = 0
6451 stat("/u01/app/oracle/diag/rdbms/test/test/ir", {st_mode=S_IFDIR|0750, st_size=4096, ...}) = 0
6451 stat("/u01/app/oracle/diag/rdbms/test/test/incpkg", {st_mode=S_IFDIR|0750, st_size=4096, ...}) = 0
6451 stat("/u01/app/oracle/diag/rdbms/test/test/sweep", {st_mode=S_IFDIR|0750, st_size=4096, ...}) = 0
6451 stat("/u01/app/oracle/diag/rdbms/test/test/lck", {st_mode=S_IFDIR|0750, st_size=4096, ...}) = 0
6451 stat("/u01/app/oracle/diag/rdbms/test/test/cdump", {st_mode=S_IFDIR|0750, st_size=4096, ...}) = 0
6451 stat("/u01/app/oracle/diag/rdbms/test/test/stage", {st_mode=S_IFDIR|0750, st