Synology enabled VAAI support for NFS in version 5.1 of their DSM software. In order to take advantage of this technology from ESXi hosts we need to do two things: Upgrade DSM to at least version 5.1-5004 (2014/11/06) Install the Synology NFS Plug-in for VMware VAAI DSM DSM can be upgraded from within the Control Panel application. Head to the Update & Restore section, check for and install updates.
During setting up an iSCSI LUN on my new Synology box (DSM 4.3), I encountered an issue where the first ESXi box would connect successfully to the iSCSI target, but not the second. So no devices showing on the second node after configuring the iSCSI adapter, despite no apparent errors during the config process. Looking at the Synology box showed the first ESXi node connected (172.20.0.210), but not the second.