Western Digital My Cloud EX4 and LenovoEMC ix4-300d Home NAS Units Reviewby Ganesh T S on February 26, 2014 2:30 AM EST
Single Client Performance - CIFS and iSCSI on Windows
The single client CIFS performance of the LenovoEMC ix4-300d and WD EX4 were evaluated on the Windows platforms using Intel NASPT and our standard robocopy benchmark. This was run from one of the virtual machines in our NAS testbed. All data for the robocopy benchmark on the client side was put in a RAM disk (created using OSFMount) to ensure that the client's storage system shortcomings wouldn't affect the benchmark results. It must be noted that all the shares / iSCSI LUNs are created in a RAID-5 volume.
We created a 250 GB iSCSI target and mapped it on the Windows VM. The same benchmarks were run and the results are presented below.
Encryption Support Evaluation
Consumers looking for encryption capabilities can opt to encrypt a iSCSI share with TrueCrypt or some in-built encryption mechanism in the client OS. However, if requirements dictate that the data must be shared across multiple users / computers, relying on encryption in the NAS is the best way to move forward. Most NAS vendors use the industry-standard 256-bit AES encryption algorithm. One approach is to encrypt only a particular shared folder while the other approach is to encrypt the full volume. In our case, only the WD EX4 supports encryption, and only on a full-volume basis.
On the hardware side, encryption support can be in the form of specialized hardware blocks in the SoC (common in ARM / PowerPC based NAS units). In x86-based systems, accelerated encryption support is dependent on whether the AES-NI instruction is available on the host CPU (not considering units based on the Intel Berryville platform). The Kirkwood SoC used in the EX4 does have a security engine, so we the performance impact should not be brutal. We enabled encryption on a a CIFS share to repeat our Intel NASPT / robocopy benchmarks. The results are presented in the graph below (with the unencrypted folder numbers for comparison purposes).
The performance of the EX4 for normal volumes was barely acceptable. Unfortunately, enabling encryption only pulls down the numbers further, most times by more than 50%. We strongly urge users looking for good encryption support to look beyond the WD EX4 and LenovoEMC ix4-300d.