The thing is nothing else has changed.
Before installing the mitigation kernel - the timings below are very typical and have been like that for several months. Backing up to a USB3 disk drive.
Incremental 0H18
==================================
DAILY BACKUP TO WORKSTATION REPORT
==================================
Backup of mailserver.xxx.xxx started at Wed Jan 3 22:15:01 2018
Destination //localhost/media/smeserver/mailserver.xxx.xxx/set4
Basename inc-006-20180103221501
Starting the backup with a timeout of 10 hours
--------------------------------------------
1827 inode(s) saved
including 44 hard link(s) treated
0 inode(s) changed at the moment of the backup and could not be saved properly
0 byte(s) have been wasted in the archive to resave changing files
309309 inode(s) not saved (no inode/file change)
0 inode(s) failed to be saved (filesystem error)
301 inode(s) ignored (excluded by filters)
500 inode(s) recorded as deleted from reference backup
--------------------------------------------
Total number of inode(s) considered: 311937
--------------------------------------------
EA saved for 0 inode(s)
--------------------------------------------
Destination disk usage 2.6T, 59% full, 1.8T available
Backup successfully terminated at Wed Jan 3 22:33:29 2018
Full - every Thursday - 3H21
==================================
DAILY BACKUP TO WORKSTATION REPORT
==================================
Backup of mailserver.xxx.xxx started at Thu Jan 4 22:15:01 2018
Destination //localhost/media/smeserver/mailserver.xxx.xxx/set5
Basename full-20180104221501
Starting the backup with a timeout of 24 hours
--------------------------------------------
309502 inode(s) saved
including 44 hard link(s) treated
0 inode(s) changed at the moment of the backup and could not be saved properly
0 byte(s) have been wasted in the archive to resave changing files
0 inode(s) not saved (no inode/file change)
0 inode(s) failed to be saved (filesystem error)
301 inode(s) ignored (excluded by filters)
0 inode(s) recorded as deleted from reference backup
--------------------------------------------
Total number of inode(s) considered: 309803
--------------------------------------------
EA saved for 84 inode(s)
--------------------------------------------
Destination disk usage 3.0T, 69% full, 1.4T available
Backup successfully terminated at Fri Jan 5 01:36:28 2018
After installing the updates, no changes to our daily operations, business carries on as usual but
Incremental that evening 1H1
==================================
DAILY BACKUP TO WORKSTATION REPORT
==================================
Backup of mailserver.xxx.xxx started at Fri Jan 5 22:15:09 2018
Destination //localhost/media/smeserver/mailserver.xxx.xxx/set5
Basename inc-001-20180105221509
Starting the backup with a timeout of 10 hours
--------------------------------------------
898 inode(s) saved
including 44 hard link(s) treated
0 inode(s) changed at the moment of the backup and could not be saved properly
0 byte(s) have been wasted in the archive to resave changing files
307668 inode(s) not saved (no inode/file change)
0 inode(s) failed to be saved (filesystem error)
301 inode(s) ignored (excluded by filters)
1473 inode(s) recorded as deleted from reference backup
--------------------------------------------
Total number of inode(s) considered: 310340
--------------------------------------------
EA saved for 0 inode(s)
--------------------------------------------
Destination disk usage 3.0T, 69% full, 1.4T available
Backup successfully terminated at Fri Jan 5 23:16:39 2018
Full the next Thursday 6H15
==================================
DAILY BACKUP TO WORKSTATION REPORT
==================================
Backup of mailserver.xxx.xxx started at Thu Jan 11 22:15:02 2018
Destination //localhost/media/smeserver/mailserver.xxx.xxx/set6
Basename full-20180111221502
Starting the backup with a timeout of 24 hours
--------------------------------------------
309683 inode(s) saved
including 45 hard link(s) treated
0 inode(s) changed at the moment of the backup and could not be saved properly
0 byte(s) have been wasted in the archive to resave changing files
0 inode(s) not saved (no inode/file change)
0 inode(s) failed to be saved (filesystem error)
301 inode(s) ignored (excluded by filters)
0 inode(s) recorded as deleted from reference backup
--------------------------------------------
Total number of inode(s) considered: 309984
--------------------------------------------
EA saved for 84 inode(s)
--------------------------------------------
Destination disk usage 3.4T, 79% full, 942G available
Backup successfully terminated at Fri Jan 12 04:30:16 2018