Introduction

It's taken a lot longer than I had figured, but Synology finally sent its DX510 Disk Station Expansion Unit in for a look. The DX510 is the expansion chassis designed to mate with Synology's five-bay DS1010+ [reviewed] and two-bay DS710+ [reviewed] NASes.

The DX510 is simple in design, consisting of a five-bay chassis that you could easily mistake for the DS1010+ that has two cooling fans, an internal power supply and controller board. The rear of the chassis (Figure 1) has only a power receptacle and single eSATA port.

Figure 1: Synology DX510 back panel

Inside

Figure 2 shows the right side of the DX510 with the cover removed, which provides a clear view of the power supply.

Figure 2: Synology DX510 inside right

Swinging around to the other side (Figure 3), we can see the little controller board.

Figure 3: Synology DX510 inside left

Figure 4 is a shot of the board, which holds some power supply circuitry, connectors for the backplane and eSATA connector, flash memory and the key player, a Silicon Image SiI3726 - 5 Drive SATA300 SATALink SATA II Port Multiplier.

Figure 4: Synology DX510 Controller board

The SiI3726's block diagram (Figure 5) shows it supports host and device link rates of 1.5 Gbps and 3 Gbps with auto-negotiation for each drive.

Figure 5: SiI3726 block diagram

In Use

Installation is very easy, consisting of plugging in an AC line cord and connecting a supplied eSATA cable between the DX510 and DS710+ or DS1010+. Although the printed User's Guide says that the DX510 will be turned on or off automatically by its companion Disk Station, I found only the auto power-off works.

You'll need to manually hit the front panel power button on the DX510 and let the drives spin up before turning on the companion NAS. This is especially important if you configure a volume consisting of drives both in the main NAS and in the DX510.

You get a warning that you'll lose such a volume if the DX510 is powered off or disconnected, which I confirmed by getting a corrupt volume when checking to see if the DX510 powered on automatically when I turned on the DS1010+ it was connected to.

The DX510 has no administration interface per se, but is configured via its companion NAS. Figure 6 shows how the DX510 shows up in the eSATA menu

Figure 6: DX510 eSATA connection detected

The DX510's drives automatically appear in the Volume Manager. Figure 7 shows a RAID 1 volume consisting of one internal drive and one drive in the DX510 (Expansion Unit).

Figure 7: Combination DS1010+ - DX510 volume

There is not a lot of online documentation available for the DX510. I couldn't find a PDF version of the printed User's Guide that came with the product. And a search of Synology's Wiki yielded only one hit about Notifications, a few FAQ hits and no "How To" Guides.

Since the info in Figure 8 is available only in the User's Guide, I thought it was important to pass it on.

Figure 8: DX510 important info