Category Archives: Synology

Enabling NFS VAAI Support in Synology 5.1

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 can be upgraded from within the Control Panel application. Head to the Update & Restore section, check for and install updates. This will likely require a reboot so ensure anything or anyone using it is shutdown or notified.




Prior to installing the NFS plugin my two NFS datastores don’t have the Hardware Acceleration support.



From the 5.1-5004 Release Notes:

Added NFS support for two primitives: Full File Clone and Reserve Space.
Please note that you should install the Synology NFS Plug-in for VMware VAAI and read the instructions in README.txt to make sure installation is successful.

Once the plugin has been downloaded it is possible to use either VMware Update Manager or esxcli to install the vib. For the purposes of my home lab without Update Manager I’m going to show you the esxcli way.

Upload the vib to a datastore all hosts can access, then the command to install the vib is:

esxcli software vib install -v /path to vib/esx-nfsplugin.vib

Once installed, the ESXi host will require a reboot


After the reboot you can check all was successful by running:

esxcli software vib list | grep nfs


and examining the NFS datastores


Synology DSM: Enabling iSCSI Multiple Sessions

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 (, but not the second.


I noticed on the above screen Multiple Sessions – Disabled. I hadn’t seen any mention of that while setting up the iSCSI LUN so looked into the config.


So it appears that multiple sessions are disabled by default, accompanied by a warning that your OS must be cluster aware. Comfortable that ESXi meets that requirement, I decided to proceed.


Multiple sessions are now available.


Rescanning the iSCSI hba and the device now appears.


Now the Synology box shows multiple sessions connected.