Hey Gaute,
You didn't flag your post with the "Insight" label, so I didn't get an email notification about this post - a lot of the OCI people are only "following" the Insight label
OCI is going to run
"C:\Program Files (x86)\EMC\Unisphere CLI\uemcli.exe" -d unity.hostname.goes.here -u OCI -p OCIisSweet! -sslPolicy accept /stor/config/pool show -detail
And report for each storage pool what the compression savings are
OCI is not reporting per individual volume compression savings - generally speaking, traditional storage arrays' per volume compression features have not been adopted by users, and OCI doesn't report per volume compression as a result. Most all flash arrays have pervasive, always on compression, and OCI tends to capture those arrays' compression at the storage pool level.
Matt