Synology DiskStation DS409slim review:

Synology DiskStation DS409slim

The DS409slim gives you access to the Photo Station feature over the Internet, just as long as you're able to set the NAS up with a dynamic Domain name system (DDNS) , or you can access the Internet with a static IP. You'll need to know quite a bit about networking in order to do this, such as how to forward certain ports to certain IP addresses, etc. Synology provides rather scant instruction regarding how to set it up, partly because this depends on each router you use. The DS409slim supports four DDNS services:,,, and

Additionally, you can use the DS409slim as a Web server, a MySQL server, a file station server, and as an audio station where you can listen to audio files contained on the DS409slim via USB speakers or stream them to other computer or devices.

The DS409slim has built-in backup options focused on getting content from the device onto a USB or eSATA external storage device or a network location. For backing up files on your computer to the DS409slim, Synology includes its Data Replicator 3 desktop software.

The Data Replicator 3 is a simple, straightforward backup application that allows you to quickly copy data (much like copying and pasting using Windows Explorer) from your computer to the DS409slim. The software includes a feature that helps you find and quickly back up e-mail archives, which are generally buried deep in layers of subfolders within a user's profile. In addition, it enables scheduling and keeping track of the backup process via e-mail notifications.

We tested the DS409slim in JBOD, RAID 0, and RAID 5 configurations and it did well in all three, though it was not the best we've seen.

In RAID 5, which is the recommended setup, balanced between data protection and disk space, the NAS server scored 191Mbps for write speed and 219Mbps for read speed. These numbers are comparable to those of most USB 2.0 direct-attached external hard drives, which are supposedly faster than NAS servers.

In RAID 0, the setup that gives you the most storage space and the best performance at the expense of data protection, the DS409slim scored noticeably faster, at 218.1Mbps for write speed and 240.88Mbps for read speed.

In JBOD setup, where hard drives are linked together without any protection or performance enhancement, the DS409slim scored 217Mbps for write speed and 228.48 for read speed.

Overall, these numbers were not the fastest we've seen, but were among the average of high-speed NAS servers. Still, considering the physical size of the DS409slim, we were happy with its performance.

The NAS also performed quietly in our tests and remained cool even during heavy loads. Note that if you have a very quiet office, you will notice the humming sound of the cool fan, however.

CNET Labs NAS performance scores via wired Gigabit Ethernet connection (in Mbps)
(Longer bars indicate better performance)
QNAP TS-239 Pro
Synology Disk Station DS409slim (RAID 0)
Apple Time Capsule
Maxtor CentralAxis (Single Volume)

Service and support
Synology backs the DS409slim with a two-year warranty from the date of purchase. Phone tech support is available Monday through Friday, 9 a.m. to 5 p.m. PST. At its Web site you can find Synology's forum, download software and the latest firmware, and get more information about Synology products from its Wiki page.

What you'll pay

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