ok, the issue was resolved. most helpful was "ages old" blog post explaining EnableResignature and DisallowSnapshotLUN EnableResignature and/or DisallowSnapshotLUN - Yellow Bricks  after setting both options to value of 0, I can execute "symrdf failover" operations without snap-xxx prefix and datastore is visible across all ESXi hosts after single datastore rescan.  as described, I am not using SRM. both SRM and SRA were uninstalled prior playing around manually with symcli commands. that also means that Paul's reply doesn't apply. and btw it is inventory - solutions and apps - storage appliances etc etc... and then right click on site to get to advanced options.
Hi all we are facing issue while testing our DR procedure. In one part, procedure consist of executing symrdf -failover on device group. after that, we are left with snap-xxx-DSNAME like datastore names rather than just DSNAME. even after symrdf -failback we are still left with that snap-xxx prefix on each datastore name.  R1 and R2 devices are preprovisioned to hosts before executing symrdf -failover. so we only do "datastore rescan" on hosts in failover site. devices are thin devices on VMAX-10k, enginuity level 5875. hosts are running ESXi 5.1.0, subver 1065491 RDF mode is sync and during DR they are in "failed over" state  we were testing SRM and SRA on this vSphere server but all was uninstalled as per documentation.  tnx in advance!
symrdf failover leaves snap-xxx prefix in ESXi5.1 datastore name