Kevin Closson's Blog: Platforms, Databases and Storage

In my recent post entitled Oracle Database 11g Database File System (DBFS) Is Not A Popular Topic. Yet., I discussed how I use Google search terms as a way of monitoring what sorts of problems people are running into with new technology such as (DBFS).

This is part one in a series of posts where I’ll offer some tips regarding the more common DBFS-related problems one might encounter in early testing. The first I’ll tackle is “Transport endpoint is not connected.”

Error Text: Transport Endpoint is not connected.
This error string occurs when attempting to access a mounted DBFS file system. The error condition arises when there is no dbfs_client currently executing that is associated with the file system.

In the following boxes I’ll show two examples of how this error can be encountered. First, I’ll show that I have a DBFS file system mounted and that an attempt to change directories to the mount point results in “Transport endpoint is not connected”, such as:

$ mount | grep dbfs
dbfs on /data type fuse (rw,nosuid,nodev,max_read=1048576,default_permissions,allow_other,user=oracle)
$ cd /data
-bash: cd: /data: Transport endpoint is not connected

A simple ps command shows there is no dbfs_client process executing:

$ ps -ef | grep dbfs_client
oracle    1694 21941  0 09:49 pts/11   00:00:00 grep dbfs_client

This error condition is quite simple to rectify. You simply need to restart the dbfs_client process:

$ export LD_LIBRARY_PATH=$ORACLE_HOME/lib
$ export ORACLE_SID=DBFS1
$ 
$ ORACLE_HOME/bin/dbfs_client dbfs@ -o allow_root,direct_io /data < /opt/oracle/dbfs/passwd.txt &
[1] 2501
$ fuse: bad mount point `/data': Transport endpoint is not connected

Sorry, I had to be sneaky in order to show one of the other conditions that raises the error. So, yes, to rectify this error condition you do have to restart dbfs_client, however, you need to first unmount the dead mount. You’ll see in the following box that I use fusermount –u to unmount and then execute dbfs_client and without any further action I can list the contents of the file system.

$ fusermount -u /data
$ $ORACLE_HOME/bin/dbfs_client dbfs@ -o allow_root,direct_io /data < /opt/oracle/dbfs/passwd.txt &
[1] 2931
$ Password:

$ ls -l /data/FS1/TEST
total 0
-rw-r--r-- 1 oracle oinstall 0 Dec 30 13:39 511b
-rw-r--r-- 1 root root 0 Dec 30 13:40 test.out

Dead Mount, Living DBFS Instance.
If you look in the boxes above you’ll notice that dbfs_client was not executing (the real root of the problem) but the instance was running. Since dbfs_client is an OCI program all I had to do was kill it to create this scenario. If, however, you suffer this error while dbfs_client is executing then I recommend involving support because that would be a bug.