Avamar backup performance of winclusterfs plug-in backup is poor after upgrading from 7.0 to 7.2

The Avamar winclusterfs plug-in is used to back up data on a share. Versions from 7.2 onward show markedly lower performance for the same dataset, even where the same node always owns the disk.

Below is a comparison of how the backup performs for different versions.

v7.3.100-233:

2016-10-05 10:50:05 avtar Info <5156>: Backup #189 timestamp 2016-10-05 10:50:05, 115,807 files, 11,387 folders, 18.03 GB (88 files, 2.336 MB, 0.01% new)
2016/10/05-08:50:05.04600 [avtar]  backup expire prectime=131202155790000000
2016-10-05 10:50:05 avtar Info <7539>: Label "MOD-1475655580409#1", scheduled to expire after 10/06/16 (2016-10-06 08:19:39 UTC), none backup, backup type: level0_full
2016-10-05 10:50:05 avtar Info <6083>: Backed-up 18.03 GB in 30.35 minutes: 36 GB/hour (228,956 files/hour)

Avamar 7.2.101-32_HF254688:

2016-10-03 10:22:20 avtar Info <5156>: Backup #179 timestamp 2016-10-03 10:22:21, 115,587 files, 11,386 folders, 18.02 GB (222 files, 2.467 MB, 0.01% new)
2016/10/03-08:22:20.70300 [avtar]  backup expire prectime=131200408610000000
2016-10-03 10:22:20 avtar Info <7539>: Label "MOD-1475480862127#1", scheduled to expire after 10/04/16 (2016-10-04 07:47:41 UTC), none backup, backup type: level0_full
2016-10-03 10:22:20 avtar Info <6083>: Backed-up 18.02 GB in 34.58 minutes: 31 GB/hour (200,536 files/hour)

v7.0.102-47: 

2016-10-03 10:36:46 avtar Info <5156>: Backup #180 timestamp 2016-10-03 10:36:46, 115,573 files, 11,384 folders, 18.02 GB (81 files, 8,158 GB, 45284.56% new)
2016/10/03-08:36:46.44700 [avtar]  backup expire prectime=131200433480000000
2016-10-03 10:36:46 avtar Info <7539>: Label "MOD-1475483348319#1", scheduled to expire after 10/04/16 (2016-10-04 08:29:08 UTC), none backup, backup type: level0_full
2016-10-03 10:36:46 avtar Info <6083>: Backed-up 18.02 GB in 7.58 minutes: 143 GB/hour (915,385 files/hour)

If the reduced performance is unacceptable, the following flag can be added to the avtar.cmd file (in the avsar directory) to skip all reparse point handling:

--x31=+33554432

This flag should be handled with care, and used only if there are no reparse points in the dataset.