Firmware version 4.0.0[13.13.89501] was loaded onto the 5N2 and performance tests were run using the Revision 5 NAS test process. All tests were run using Western Digital Red 1 TB WD10EFRX (x4 SNB supplied). Although the sample 5N2 Drobo provided had an mSATA SSD installed, that's not the stock configuration. So I removed it for most testing.
Since Drobo doesn't allow direct control of RAID levels, I can't fairly directly compare it to other NASes in the charts. In fact, I created a new "Auto" class so the NAS Ranker wouldn't mix it in with RAID5 class products. But since the 5N2's default mode is single disk redundancy and a four-drive volume was used, results are posted in the NAS Charts as RAID5.
The benchmark summary below show performance typical of today's NASes, i.e. file copy of large continuous files pretty much max out the capacity of a Gigabit Ethernet connection. The main exception is NASPT File Copy to NAS (write), which is about 10 MB/s low compared to the other File Copy results.
For comparison, I chose a typical mid-range NAS, Synology's DS416. It costs around $350 vs. the 5N2's $499 and is powered by a dual-core Annapurna Labs Alpine AL-212 vs. the 5N2's quad-core Marvell Armada XP. The comparison shows only one other benchmark where the Drobo's performance significantly lags: NASPT Directory Copy to NAS.
Benchmark summary comparison
I also rans tests in the following modes shown in the chart below to see how performance varied:
- 1 Drive, No Cache: This is the data entered into the NAS Charts, taken with default single drive redundancy and no SSD cache. It would be the default performance for a stock 5N2 with four drives.
- 1 Drive, w/ Cache: Same as above, but with SSD cache installed.
- 2 Drive, No Cache: SSD cache removed, dual-drive redundancy enabled and volume resync completed.
- Volume Build: Test was run while volume was being changed from single to dual-drive redundancy.
Drobo 5N2 - Performance vs. modes
SSD cache doesn't provide any benefit in these tests because the benchmarks are designed to defeat cache effects. The results also show no performance penalty (or advantage) when using dual-drive redundancy. The only price paid there is lots of storage capacity.
There is a significant read hit when volumes are being rebuilt, but that's to be expected.
There may be many reasons you would not choose a Drobo as your NAS, but performance is no longer one of them. Sure, you'll pay a price premium for the benefit of being able to painlessly expand storage capacity and use whatever 3.5" drives you have lying around. But Drobo will move those large media files around as well as most any other NAS you can buy.
I'd really like to see Drobo provide more options for backing up its files. Backup via standard rsync would be a minimum; backup via SMB and FTP like NETGEAR ReadyNAS has would nice additions, too. As robust as Drobo is, hardware failures do happen, as do fire and theft.
If you want to easiest and surest way of expanding storage if and when you need it and don't mind paying more, then you should check out Drobo's 5N2.