ReplicatorV2 from Celerra to VNX poor Performance

Hello Everyone,

at the moment i have to migrate some Filesystems from an old Celerra to a new VNX5300. The Replication works, but is very Slow. There is a 1Gbit Link between the Datamovers without Firewalls. I have a Bandwith Throttle Configured with 500Mbit´s and with 4 Sessions i only get round about 12-15MB´s.

Anyone seen this before and had some Troubleshooting Tips for me?