To avoid the possibility of path thrashing, disable Auto Volume Transfer (AVT) on the SAN storage processors. If AVT is enabled, the two storage processors can alternately take ownership of the LUN in certain situations, resulting in performance degradation. AVT is also known as ADT (Auto Disk Transfer).
To disable AVT, in the DS 4800 Storage Manager, for each port defined in each host group that contains HBAs for one or more ESXi hosts, set the host type to LNXCL or, in later versions, to VMware.
You must reboot the hosts after you change the AVT configuration.