I/O's were failed after attaching the tier is because, the fix-layout was not complete for some directories. So the directory structure was not proper on hot tier, and then trying to access such directories will result a failure. Fix : after a nameless lookup if we get an incomplete layout, we will trigger a healing after getting full path from the server.
This bug is getting closed because a release has been made available that should address the reported issue. In case the problem is still not fixed with glusterfs-3.7.7, please open a new bug report. glusterfs-3.7.7 has been announced on the Gluster mailinglists [1], packages for several distributions should become available in the near future. Keep an eye on the Gluster Users mailinglist [2] and the update infrastructure for your distribution. [1] https://www.gluster.org/pipermail/gluster-users/2016-February/025292.html [2] http://thread.gmane.org/gmane.comp.file-systems.gluster.user