How To Back Up NAS to NAS – Part 1

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Tim Higgins


The NETGEAR ReadyNAS NV+ that I have been using as my main NAS has started acting flaky lately. It has more than once made my heart skip a beat when it emailed to report that its RAID 1 volume was "destroyed". Fortunately, it was somehow confused, because I found the volume intact when I logged in and checked.

But after a few of those alerts and finding errors when I performed a boot time volume scan (despite no indication of disk problems via SMART), I decided it was time to look into replacing the ol’ girl. (In the meantime, I also took a guess and replaced Drive 2, so we’ll see if I guessed correctly.)

Since Smart SOHOs Don’t Do RAID, I have advocated a pair of single-drive NASes as a robust and cost-effective storage strategy. The single drives remove the potential complication of RAID and the separate hardware allows primary and backup storage to be both electronically and physically separate. As long as the two NASes you choose have compatible NAS-to-NAS backup features, you’ll be able to set up completely automatic backup to keep your data nice and safe.

Right now, this approach is applicable if your storage needs can live within the formatted capacity of a single 2 TB drive, or perhaps 4 TB if you’re willing to use a dual-drive NAS configured in JBOD or two 2 TB volumes. Since my storage needs don’t even crack the 100 GB barrier and are unlikely to do so anytime soon, single drive solutions work just fine for me.

This series will bring you along on my journey to find a replacement storage system to replace the ReadyNAS NV+ / (original model) Buffalo LinkStation pairing that I currently use. As I noted in Backing Up Your NAS: Harder Than It Should Be, the process isn’t quite as simple as it should be. But where that article just touched on some of the barriers to success, this series will provide more detail on the problems that I encountered and the solutions that I found. So, to kick things off, let’s look at how I fared with my first candidate—Synology’s DS109+.

Moving Data Off The NV+

The good news is that ReadyNASes are the most flexible NASes when it comes to networked backup, supporting bi-directional backup via SMB/CIFS (any networked share), HTTP, FTP, NFS and rsync!

Figure 1 shows a screenshot from the NV+ backup job wizard that details the options. The NV+ has also been great as a backup NAS because it is one of the few products that will back up more than once a day (4, 6, 8, 12 or 24 hours, to be precise).

NETGEAR ReadyNAS Backup options
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Figure 1: NETGEAR ReadyNAS Backup options

My first step was to get the data moved from the NV+ to the new primary NAS. While I could have just mounted the shares on both NASes on a networked machine and done a drag-and-drop copy between the two, I figured I might as well see if I could get the NASes to handle the job between them.

Of the networked backup options that the NV+ supports, rsync seems to be the most widely-supported non-proprietary option. As luck would have it, I still had the Synology DS109 and 109+ from their recent review. Since Synology NASes support networked backups via "Synology server" and "rsync-compatible" server options, it looked like I had a shot. I chose the 109+ because it’s a bit faster than the 109.

I asked Synology what the difference was between the "Synology server" and "rsync-compatible" server options. They replied that the "Synology server" option is just rsync with easier setup—choosing the server and entering the password.

Not So Simple

The first thing I had to decide was whether I should use the NV+ or 109+ to run the copy. But it turned out that I didn’t really have a choice. Although the Synology has a backup utility, it’s one-way only, i.e. you can only choose an rsync partner as a destination, not a source for the copy.

So I turned to the NV+ and tried to set up a backup job, but it was a frustrating experience. Neither Synology nor NETGEAR provide enough information in the products’ online help or documentation to get the products set up successfully. And even digging through Forums and FAQ only got me part of the way there.

Figure 2 shows the NV+ backup wizard with settings that finally allowed me to successfully connect to the 109+. The Host is the 109+’ IP address and the Path is actually the rsync module name, but without the double colon ( ::) that normally is used as an rsync module delimiter.

Synology rsync destination settings

Figure 2: Synology rsync destination settings

NetBackup is actually one of the Synology default shares and is visible when you browse for shares. But it’s the only share that can be connected via rsync. So I wasn’t able to have my current shares on the NV+ be exactly duplicated on the 109+ as top-level shares. Instead, they had to be copied to folders in the NetBackup share.

The trickiest part, however, was determining the Login and Password information. This Synology FAQ led me to believe that I could enter either root or rsync in the NV+’ Login (username) field. But I wasn’t successful with either one.

I had too many variables—Path (I hadn’t yet figured out to not include the ::), Login and Password—and was getting nowhere by guessing. So I finally resorted to enabling SSH via the 109+ Network Services > Terminal page, logging in and looking at the /etc/rsyncd.conf file, which is shown below.

Syno_DS109plus> cat /etc/rsyncd.conf
#motd file = /etc/rsyncd.motd
#log file = /var/log/rsyncd.log
pid file = /var/run/
lock file = /var/run/rsync.lock
use chroot = no
path = /var/services/NetBackup
comment = Network Backup Share
uid = root
gid = root
read only = no
list = yes
auth users = root
secrets file = /etc/rsyncd.secrets 

The [NetBackup] confirmed the rsync module name (it’s always found in brackets in the rsyncd.conf file. And since the uid and gid were set to root, I figured it was a better bet than using rsync as the Username / Login name.

So now the only thing left was the password and neither root nor admin worked. I found the final clue here, which revealed that my problem was that the 109+ did not have an admin password set. Once I did that, and entered it in the Password field, a click on the NV+ Test Connection button finally produced the Successfully Connected to popup that I was waiting for.

Now that I had a working connection, I set up backup jobs in the NV+ for each folder / share that had to be backed up. I also set up folders in the NetBackup folder with names to match the shares being copied. The only thing I needed to change for these jobs from the NV+ backup job information shown in Figure 2 was the Path. My NV+ media and backup folders required Paths of NetBackup/media and NetBackup/backup, respectively.


With an rsync success under my belt, I decided to try the 109+’ Download Station feature to copy folders from the NV+ via FTP. Synology’s Download Station Settings (Figure 3) show controls for download via HTTP, FTP, BitTorrent, eMule and even news server NZB files.

Synology Download Station settings
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Figure 3: Synology Download Station settings

So I figured I just needed to enable the NV+’ FTP server, then enable FTP permissions on the backup and media folders that I wanted to transfer. But when I did that and tried to start a download from, I would just get a Broken Link returned for the transfer status (Figure 4).

Download Station Broken Link

Figure 4: Download Station Broken Link

Once again, the devil was in the details. I found this thread in the Synology Forums that provided the answer that the Download Station supports file downloading only. So, for now, at least, if you’re trying to do NAS-to-NAS backup with Synology NASes, rsync is the only option that you have.

Next time, I’ll see what we can do with a QNAP NAS.

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