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QNAP TS-239 Pro II VMware Performance – NFS vs iSCSI

May 1, 2013

I recently purchased a QNAP TS-239 PRO II+ 2-bay NAS and wanted to establish a performance baseline for future troubleshooting.  I was surprised to find that in almost every test NFS outperformed iSCSI.  For details on the configuration and performance tests I conducted continue reading.

Storage Configuration

QNAP TS-239 Pro II Intel Atom powered 2-bay NAS (firmware 3.8.3) populated with a single Seagate ST3000DM00 3TB 7200 RPM Barracuda 3.5″ Internal Desktop Hard Drive.   The Seagate Drive is listed on the QNAP 3.5″ HDD Compatibility List.  The QNAP has also been upgraded to 2 GB of memory using a Kingston KVR667D2S5/2G SODIMM.  The NFS Datastore was configured as an EXT4 file system with File Locks (Oplocks) enabled (default).  A 1024 GB iSCSI LUN using Instant Allocation on the was created for iSCSI.

Note: I also used a SAMSUNG 830 Series 128GB Solid State Drive (SSD) for NFS testing and found no noticeable improvement in performance for this configuration.

Host Configuration

Apple MAC mini Quad-core i7/2.3GHz/16GB, VMware vSphere ESXi 5.1 u1 installed on a local Samsung 840 Pro Series 2.5-Inch 256 GB SATA Solid State Drive (datastore1).

Network Configuration

The Management and VM Network on (vSwitch0) are connected to the 192.168.1.x network using the onboard Broadcom BCM57766 network adapter (vmnic0).  vmnic0 is connected to a Cisco 3560 Compact Switch (WS-C3560CG-8PC) and is not used for Storage traffic.

A VMkernel Port configured with the IP address ( was created on a second vSwitch (vSwitch1). The Apple Thunderbolt to Gigabit Ethernet Adapter BCM57762 (vmnic1) is directly connected to Ethernet Interface 2 ( of the QNAP TS-239 PRO II+ with a BELKIN 1′ Cat6 Patch Cable.

There are several methods for testing storage performance, I decided to use the following:

Virtual Appliance – VMware I/O Analyzer Results

In the VMware I/O Analyzer Results NFS read throughput (IOPS) is 18.98% better than iSCSI and read bandwidth (MB/s) is 19.49% better.   NFS write throughput (IOPS) is 42.3% better than iSCSI and write bandwidth (MB/s) 42.28% better than iSCSI.  The NFS Read Throughput bandwidth is equal to the Ram-to-Ram Network Performance numbers recorded in tom’s HARDWARE article Gigabit Ethernet: Dude, Where’s My Bandwidth?

I placed the VMware-io-analyzer-1.5.1 virtual machine on the NFS datastore (NFS01), and achieved the following results.

Max_Throughput.icf (Read) 222.45 111.2
Max_Write_Throughput 181.25 90.62

In the second test I enabled the Software iSCSI Initiator on the ESXi host and added the 1024 GB iSCSI LUN as a VMFS-5 datastore (QNAP-20130622203046).  I placed the VMware-io-analyzer-1.5.1 virtual machine on the iSCSI datastore, and achieved the following results.

Max_Throughput.icf (Read) 186.12 93.06
Max_Write_Throughput 127.37 63.69

Virtual Machine – HD Tune Pro and Intel (NASPT) Results

A Windows Server 2003 R2 Enterprise Edition -SP2 virtual machine was used for the HD Tune Pro 5.50 and Intel NAS Performance Toolkit (NASPT) tests.  The virtual machine is configured with a single vCPU, 1024 MB of Memory, and a single vNIC connected to the VM Network Virtual Machine Port Group.  The operating system is installed Samsung Electronics 840 Pro Series 2.5-Inch 256 GB SATA Solid State Drive (datastore1) using an 8 GB Thick Provision Eager Zeroed .vmdk file (Hard disk 1). An additional 80 GB Thick Provision Eager Zeroed .vmdk file (Hard disk 2) which was created on the NFS or iSCSI datastore for testing.

In the HD Tune Results NFS average read bandwidth (MB/s) is 42.32% better than iSCSI.   NFS average write bandwidth (MB/s) is 61.09% better than iSCSI.  The NASPT Results show that File Copy to NAS iSCSI is 27.59% faster than NFS and File Copy from NAS NFS is 36.84% faster than iSCSI.

HD Tune Results – 80 GB (Hard disk 2) .vmdk file – NFS datastore


HD Tune Results – 80 GB (Hard disk 2) .vmdk file – iSCSI datastore


Intel NASPT NFS Results (left) and iSCSI Results (right)


Desktop PC – File Copy Results

The Desktop PC is a Microsoft Windows 7 Lenovo ThinkCentre m92p Tiny Desktop computer with an Intel Core i5-3470T Processor (3M Cache, 2.90GHz), 8GB PC3-12800 DDR3 Memory, Samsung 830 Series 128 GB SSD, and an Integrated Intel Gigabit Ethernet connected to the Cisco 3560 Compact Switch (WS-C3560CG-8PC).  A 3.09 GB Microsoft Windows 7 .iso image (en_windows_7_professional_with_sp1_x64_dvd_u_676939.iso) was used for the File Copy Tests.

Datastore Browser Results revealed that NFS Upload Bandwidth (MB/s) was 859.55% faster than iSCSI and NFS Download Bandwidth (MB/s) was 36.73% faster than iSCSI.

Datastore Browser Results

Up Down
NFS 55.75 53.75
iSCSI 5.81 39.31
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