There are two RHEL 7.2 linux servers located in different places. Both have same directory structure. Requirement is to keep certain directories of both servers in sync, i.e any modification in server1 should get reflected in server2 and vise versa, but if some file gets deleted locally it should not get deleted from remote server also. If some files get modified while link between those two servers is down, it should be copied as soon as link gets established.To implement this following script is made :
#!/bin/bash EVENTS="CREATE,MOVED_TO,MODIFY" inotifywait -e "$EVENTS" -m -r --format '%w%f' --fromfile list.txt| while read FILE; do echo $FILE returnvalue=1 while [[ $returnvalue -ne 0 ]] do rsync -azr $FILE backupserver:/$FILE returnvalue=$? echo $returnvalue if [[ $returnvalue -ne 0 ]] then sleep 60 fi done done
list.txt contains all the directories to be monitored. This is script is running in both the servers.
Problem : Whenever some modification is made in server1, it detects and copies it to server2 with return code 0. But that is detected in server2 as new modification and it tries to copy back to server1, as that file is present in server1 rsync returns an error code 23, so programs gets stuck.
What is the best solution to this problem?
Note: We cannot use --ignore-existing option as same file exists in both places which needs to be updated if content gets changed.