The TS-639 Pro is a six-bay BYOD NAS that can take up to 1.5 TB SATA hot-swappable drives. Supported volume configurations include single, JBOD, RAID 0, 1, 5, 5+ spare, and 6. Online RAID expansion and RAID level migration are supported. Internal drives are formatted with EXT3.
The 639 Pro is the first NAS we have seen to use Intel's Atom CPU, specifically, the N270 @ 1.6GHz. This is backed by 1 GB of DDRII RAM and dual Gigabit Ethernet ports that can be configured in failover, 802.3ad aggregation and individual modes and support 4, 7 and 9 K jumbo frames.
Five USB 2.0 ports can be used for USB flash and hard drives for expansion, USB printer serving and UPS shutdown synchronization. There are also two eSATA ports for storage expansion. There is also a VGA port that supports full console and root access if you attach a monitor and USB keyboard and mouse.
Backup to attached USB or eSATA drives can be scheduled once daily with selected days of the week. NAS-to-NAS backup is supported to another QNAP device or rsync server once per day, week or month. The connection can be optionally encrypted via SSH with file compression and incremental replication options.
Power consumption was 73 W with six Samsung HE103UJ500 1 TB drives that QNAP provided for testing. Fan noise is medium, meaning the NAS is clearly audible in a quiet room with multiple computers running. Drives can be scheduled to spin down after between 5 and 60 minutes of inactivity, which reduced power consumption to 34 W. Shutdown, startup and restart can also be scheduled daily, weekly on the weekend or on specific days.
CIFS/SMB, AFP and NFS network file systems are supported, and files can also be accessed via FTP and secure (SSL/TLS) FTP. HTTPS is supported for admin access. Up to eight iSCSI targets can be configured.
Media features include iTunes and UPnP AV / DLNA (Twonkymedia) servers and there is a download service for HTTP, FTP and BitTorrent files.
The TS-639 Pro turned in an average RAID 5 write performance using a Gigabit Ethernet connection of 60.3 MB/s for file sizes between 32 MB and 4 GB, with cached behavior not included in the average calculation and a four-drive array. Average RAID 5 read performance was slightly higher, measuring 63.1 MB/s with the same conditions.
File copy performance using a Vista SP1 client under the same conditions (RAID 5, Gigabit LAN) measured somewhat lower at 54.1 MB/s for write but significantly higher at 81.7 MB/s for read, ahead of the Thecus N7700, but behind the NETGEAR ReadyNAS Pro.