A surprising change on the Duo v2 is the lack of support for jumbo frames. Both the Duo v1 and v2 have Gigabit Ethernet interfaces, but the v2 is limited to file transfers with 1500 byte frame sizes. The older v1 is configurable to support jumbo frames up to 7936 bytes.
However, jumbo frames today don't provide the throughput boost they used to. Current generation Ethernet NICs and processor architectures ensure that bits move across the wire as speedily as possible without using jumbo frames. SmallNetBuilder stopped testing NASes with jumbo frames enabled a few years ago, when we started to find they tended to reduce, rather than increase throughput. So don't let the v2's lack of jumbo frame support stop you from considering it.
The Duo v2 was put through our standard NAS test process with ReadyNAS RAIDiator 5.3.6 firmware running on the Duo v2. The Benchmark summary below shows write performance on the Duo v2 is significantly lower than read performance for both RAID 0 and RAID 1 for the Windows file copy benchmark. RAID 0 measured 56 MB/s and 85 MB/s write and read, while RAID 1 was 50 MB/s and 87 MB/s.
ReadyNAS Duo v2 Benchmark Summary
When looking at the Intel NASPT File Copy results, write and read speeds are somewhat more evenly matched, but still not equal. Those benchmark results were 44 MB/s and 40 MB/s for RAID 0 write and read, while the RAID 1 benchmark produced 41 MB/s and 50 MB/s.
We also ran the Benchmark test suite with the two drives configured in X-RAID2. Table 2 compares NASPT File Copy To and From results for RAID 0, RAID 1 and X-RAID2. You can see there isn't a significant performance difference among the different volume configurations. Obviously, the value to X-RAID2 is not performance, but the ease of disk expansion and replacement, as discussed earlier.
|Component||RAID 0||RAID 1||X-RAID2|
|File Copy To||44||41||42|
|File Copy From||40||49||50|
Table 2: Volume mode performance comparison
There are no iSCSI results, because the Duo doesn't support it.
We were able to measure attached backup throughput with our test drive formatted in FAT and NTFS and with USB 2.0 and 3.0 connections. The best results of 60 MB/s were obtained with a USB 3.0 connection and FAT formatted drive. Network backup using rsync came in at a respectable 29 MB/s.
For a competitive look, I used the NAS Finder to find two-bay 1.6 GHz Kirkwood-based NASes and came up with three others tested with the current benchmark process: the ZyXEL NSA325; Iomega ix2-dl and Buffalo LinkStation Pro Duo LS-WVL. I unfortunately was not able to include the original Duo in the comparison, because it was tested with an entirely different benchmarking process.
I can provide one data point for v1 and v2 comparison, however. I copied a 4.8 GB file from the same Windows 7 PC to my v1 Duo and the review sample v2, with all network conditions identical. It took 6.5 minutes to copy the file to the Duo v1 (~12 MB/s) and less than 2 minutes (~40 MB/s) to copy the file to the Duo v2!
The plot composite below shows Windows and NASPT RAID 1 file copy write and read results for the four NASes. The products shift positions in the various comparisons. But in three out of four comparisons, the ZyXEL takes the top slot. It's interesting that four products that all use essentially the same hardware design differ so much in performance. Just shows you what a difference firmware can make!
RAID 1 performance comparison
As an overall network storage device, I found the Duo v2 greatly improved over the Duo v1. The admin menus are improved, the internal processor is more powerful and it can handle larger internal drives and faster external drives via USB 3.0. All this makes for an easier to use and higher performance product.
The biggest negatives I found were the problems with ReadyNAS Remote and the features that depend on that service, including ReadyDROP. NETGEAR tech support acknowledged there are problems with these features and RAIDiator 5.3.6. So I hope a solution is coming soon.
I ran a quick price comparison of the four NASes compared above. Keep in mind the Buffalo comes with two 1 TB WD Green drives. So subtracting the current $160 price for two drives, that brings the Buffalo's equivalent diskless price to $115! The bottom line from this quick comparison is that NETGEAR has priced the Duo v2 at a slight-to-large premium to products with similar hardware platforms.
|Iomega StorCenter ix2-dl||$151|
|NETGEAR ReadyNAS Duo v2||$185|
|Buffalo LinkStation Pro Duo (w/ 2 TB)||$275|
Table 3: Price comparison
To sum it up in simple terms, the Duo v2 is faster, quieter and more fully-featured than the original. But if you are looking for a bargain RAID 1 NAS, the ZyXEL NSA325 could be a better price/performance choice, as long as you are not also looking for the feature set and polish of the Duo v2.