Huge DLO network traffic
We deployed DLO to some users at a branch office which is just some kilometers away.
NBU DLO 6.1, SQL, and storage location is at HQ data center. WAN link is 30 Mbps MPLS.
DLO profile is configured to use incremental message level and VSS method for PST, and Delta Transfer for all other file types. The DLO job is scheduled twice a day during office hour.
We have been seeing DLO users consume huge volume WAN traffic which does not make sense compared to amount of the data being selected by the profile. For example, one user has about a total 6 GB of data stored in his NUDF, out of which his PST file is only about 1 GB. After the initial transfer, DLO is supposed to transfer incrementally, but it's not happening. We monitored the WAN traffic and found that his machine consumed 8-10 GB per day, yest his NUDF is growing only a little. We run continuous ping between HQ and branch office and there is no packet drop at all. WAN pipe is not congested.
We looked on his DLO Agent console and found that during the "Copying network" stage of PST the progress bar shows many 'connection drops'. When the progress bar reach some random percentage (30% - 80%) suddenly it starts over from 0% and this repeats many times. Therefore even when there is only small changes were made to the PST, it consumed huge WAN traffic.
We tested the same profile in HQ LAN and found that the DLO Agent transfer only small amount of PST data even though the progress bar shows as if the whole 1 GB PST is transferred.
What could be the reason for this?