This bug has been copied from bug #733416 and has been proposed
to be backported to 5.7 z-stream (EUS).
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
Technical note added. If any revisions are required, please edit the "Technical Notes" field
accordingly. All revisions will be proofread by the Engineering Content Services team.
This update introduces support for jumbo frames in the Xen networking backend. However, old guests will still revert to a 1500-byte MTU after migration. This update also changes how the guest will probe the backend's Scatter/Gather I/O functionality. As long as a recent enough kernel is installed in the destination host, this will ensure that the guest will keep a large MTU even after migration.