Seems like a bunch of NASes that use 2.5" SATA drives have been hitting the shelves this year. The new models from QNAP, Synology and Thecus actually aren't the first consumer NASes to features 2.5" drives. That distinction goes to the Buffalo LinkStation Mini, which appeared around the middle of last year.
This newer crop, however, are BYOD NASes and include models with drive trays with mounting holes (and included screws) for both 2.5 and 3.5" drives and smaller-footprint products that accept only 2.5" drives.
QNAP is perhaps the biggest booster of 2.5" NASes, having changed over to 2.5" / 3.5" support across its newer Intel-based models and introducing two 2.5"-only models, the SS-439 Pro and SS-839 Pro (Figure 1).
Figure 1: QNAP SS-839 Pro
Synology introduced the DS409slim and added a 2.5" disk holder that can be used in their one, two and four-drive current-generation "9" series models. The new DS409 doesn't actually need the adapter; it can accept either 2.5 or 3.5" drives.
Thecus' N0503 (Figure 2) accommodates 2.5 and 3.5" drives with an interesting approach—a plug-in card cage for five 2.5" drives.
Figure 2: Thecus N0503
My first impression was that these vendors were just trying to create sales with a gimmick for buyers who wanted a NAS with a smaller footprint, lower power draw and lower noise. And I thought that using 2.5" drives would mean sacrificing performance, so decided to run some tests.
Western Digital was kind enough to loan me two 320 GB Scorpio Black (WD3200BJKT) drives, which spin at 7200 RPM and have 16 MB of cache. I loaded the drives into a QNAP TS-239 Pro that was upgraded with new trays that accept both size drives and ran the standard NAS Chart tests in both RAID 0 and 1 volume configurations using EXT4 formatting and a Gigabit network connection.
I then swapped out the WD drives for a pair of 1 TB Seagate Barracuda 7200.11 (ST31000333AS) 3.5" drives and reran the tests, again using EXT4. I also took the original test data from the TS-239 Pro review, that was taken using two 1 TB Samsung Spinpoint F1 (HD103UJ) 3.5" drives formatted in EXT3.
Figure 3 shows the results for the three sets of drives for the Vista SP1 filecopy benchmark tests. Read results for both RAID 0 and 1 are virtually identical between the WD 2.5" and Seagate 3.5" drives. And the 2.5" Scorpio Blacks actually do a bit better than both the 3.5" drives for RAID 0 write!