[DSS V7] What does Error 12 means in data replication?

Additional information:

• product name: DSS V7
• product version: all versions 
• build: all versions 

Problem:

I'm trying to run data replication, but I got "Error 12" what does that mean? 

Symptoms:

The occurrence of "Error 12"

Solution:

When using the Data Replication and receiving  “Error 12” this can mean the following.

1. The destination disk is full (remember that you need at least the size of the largest file that needs to be updated available in free disk space for the transfer to succeed). 

2. An idle connection caused a router or remote-shell server to close the connection.

3. A network error caused the connection to be dropped.

4. The remote rsync executable wasn't found.

5. Your remote-shell setup isn't working right or isn't "clean" (i.e. it is sending spurious text to rsync).

6. Some Disk IO errors - check RAID Health or disks.