Error Troubleshooting

Issue: Error occurs when attempting to monitor a directory

If you are attempting to monitor a directory on a Linux system (i.e., you are running async in continuous mode), you may receive the following error:

Failed to set up directory change notification - reached the per-user limit on number of inotify watch descriptors.

Cause:

You have exceeded the per-user limit imposed by the OS on the number of directories that may be monitored (i.e., the number of inotify watch descriptors).

Solution:

You will need to modify your kernel parameters to change the maximum number of user watches. Note that the following procedure may differ by distribution. Please check the Linux Administrator's guide for your specific distribution. To start, open the following file in an editor on your Linux machine (Redhat, Centos, Fedora or Ubuntu) for editing:

/etc/sysctl.conf

Change the maximum number of user watches in the .conf file (where the number is chosen to exceed the maximum number of directories ever expected to exist under the doc root monitored by async).

fs.inotify.max_user_watches=1000000

Save changes and run the following command to load the configuration changes: 

[root@~]# sysctl -p 

To check that the changes have been applied, run the following commands:

[root@~]# sysctl -a | grep max_user_watches  
fs.inotify.max_user_watches=1000000

Issue: async client displays failure to start sync error

When the async binary on the remote computer cannot initialize, the async client gets a generic error similar to the following:

Failed to start sync session

Cause:

There are several possible causes.

• async binary doesn't exist (or is not in the path and sshd cannot find/execute it).
• async binary cannot be run.
• async binary cannot initialize properly (e.g., if the system is out of memory or socket resources).
• async binary cannot create its log files, if specified with -R (bad path, bad permissions).

Solution:

Check your system for the possible causes above.

Issue: You receive an error when performing a sync from Linux to Windows.

When you attempt to perform a sync from Linux to Windows, you receive the following error:

Failed. Peer error: Symlink policy copy not supported on Windows peer.

Solution:

You must specify -n skip or --symbolic-links=skip when performing the sync.