Features and Functions
The physical designs of the two products are very similar. Both have you insert naked 3.5" SATA drives by sliding off the front cover and just pushing the drives into place—no tools or mounting trays required. Both front panels have activity LEDs for each drive along with a LAN Link / Activity light. Rear panels are very similar with the main difference being the missing USB connector on the 321.
The 323 originally did not support gigabit jumbo frames, but the recent 1.05 firmware release added support for up to 9k frames. Although there's nary a mention to be found of jumbo frames in all of the 321's documentation and marketing material, a check with D-Link revealed that up to 9K jumbo frames are supported on the 321. There are no jumbo frame enables or controls in the 321's LAN settings, but my testing verified that they are, indeed, supported.
The 323 review does a good job of describing most of the 323 and 321's features, so I won't repeat that information here. With the exception of USB print serving and BitTorrent support in the Download manager, you'll find all the 323's features in the 321. Instead, I'll cover two things that review didn't cover: the Download feature and RAID 1 failure and recovery.
You won't find the Download Scheduler in the main admin interface. Instead, you reach it via the Downloads button on the 321's login screen (Figure 2).
Figure 2: Login screen
One you're logged in, you'll see the Schedule Downloads screen (Figure 3). You can enter FTP or HTTP URLs that point to either single files or folders, or local networked shares using UNC notation (ex. \\servername\dir\filename.txt)
Figure 3: Schedule Downloads screen
In Figure 3 I have entered the URL to the 321's Linux file on D-Link's FTP server, which I was able to test using the handy Test button. You then browse to select the 321's folder where the file(s) will be stored (Figure 4).
Figure 4: Download "Save To" browsing
Accustomed to clicking on the folder, not the filename in Windows, I clicked in circles for a few minutes, wondering why I couldn't get the Save To destination to stick. I finally stumbled upon clicking on the filename and that did the trick. Note that you can also create a new folder, but that destination doesn't automatically get saved as the desired destination.
Before your scheduled download time, a Start button will appear on the Schedule List so that you can kick off a download on demand. When a download is running, the button changes to Stop as shown in Figure 3. Figure 5 shows the Status screen, which inconveniently doesn't offer the same Stop buttons.
Figure 5: Download Status
The Schedule list uses icons to indicate download status. But the icons don't have tooltip explanations and they are not described in the User Manual. The floppy disk icon with an "X" on it wasn't hard to figure out, but the floppy with an "O" on it wasn't crystal clear.
Recurring backups can be scheduled for Daily, Weekly or Monthly, but I would also have liked an hourly option. You can enable Incremental backups, but only if you are downloading locally. In all, once you get used to the interface quirks, the feature seems to work well.