When users access Excel documents stored at mapped network shares (deployed with a NetApp storage solution), the time to update gets really high. As an example to update a 6Mb Excel file over a connection with 38 ms latency takes more than 40 seconds.
Before performing further exploration, let me clarify that the 38ms latency are WAN latency. We have a MPLS line between two of our sites separated by 500km. The network latency between those two sites is arround 38 ms.
Is this situation a show stopper? Does it explain the poor performance?
Yes, that's a show stopper : WAN latency is outside of storage problem. Basically, no matter how fast your storage is serving up the files, but if it has to go through 38ms WAN latency then the end result will be slower, even though storage is at no fault.
I am assuming the 'end-users' are accessing the 'mapped-share' over a WAN. If so, can we not have something cached locally ? I see two options here :
1) Using DFS 2) Using FlexCache Volumes <-- This will need another Filer placed near the branch-office, this way cache all 'hot-data' locally at user-end side, and only those blocks that are not available locally will need to be fetched from the source filer where the shares resides. This is a new solution, and it's not like mirrored relication, this is a proper Read/Write volume.
For more inofrmation on flexcache volume there is some info on this TR, it's available on net:
FlexCache Volumes in NetApp ONTAP ONTAP 9.5 Chris Hurley, NetApp November 2018 | TR-4743
Flexcache in ONTAP 9.5: Using a FlexCache volume in a storage system that is deployed at a remote site and connected to the cluster over a Wide Area Network (WAN), can help in situations such as distributing read-intensive data across multiple locations