I am not sure about this setup.
Are you saying you use uncompressed data to write it into the FAS2720 and then get 50% reduction with inline compressions? This is expected.
I was not sure either but very curious about it
When you would use the Veeam compression instead of the FAS2720 one you will end up with 2x the backup target performance as the target has to handle only half of the data
The source is the bottleneck and throttling pop up quickly since they have a high average load. Write speed averages 100MB/s and Network bandwidth isn't really an issue.
As well make sure that the post dedup run is scheduled to be run outside of the backup window.
I would always use in this setup iSCSI + XFS block cloning with Veeam compression. If you really like you can enable deduplication within the storage afterwards. Not ideal but it should give you good performance with good space savings.
Yes post-dedupe,post-compression outside the hours and set on the best effort so It should not impact performance much even if it runs at the same time. I did that test before, it gives you a little extra 15-18% indeed to enable post-dedup with block-cloning.
I tend to use block cloning as well because e don't have many customers who can afford FAS type as a backup repo and when they do we have a Snapshot, Snapmirror or Snapvault involved at some point.
The "plus" of this approach is we get back dedupe/compression lost by per-vm settings since it is applied a volume level. The trade-off is your basically cut in half your maximum write speed as you mentioned it, no Synthethic allowed and you need to keep enough space on your volume for the post-processing.
I will be happy to share some data later.
Oli