Of course, the real value of the CDP 110 isn't the hardware, but what it does. As described in my previous review, Continuous Data Protection (CDP) is different than traditional backup. CDP uses a technology that monitors file changes and backs up only the changes as they occur, instead of backing up the entire file on a predefined schedule.
Let's start with device management. SonicWall provides a secure web interface (https://<deviceIP>) for system management.
Figure 3: Status screen
Network configuration is on the Network > Settings page where you must configure the CDP with a static IP address—it does not support DHCP. The default IP address is 192.168.168.169/24, so you first have to configure a PC on this subnet and change the IP address of your CDP 110 to get it to connect to your LAN.
In addition to Network configurations, the web interface provides utilities for system status (Figure 3), configuring system time, diagnostic information, software updating and licensing, erasing the hard drive, resetting the device, and some basic reports.
The diagnostic information is basic Linux console output, reflecting the fact that the CDP runs on SonicLinux, SonicWall's customized version of Linux. Reporting capability through this interface is limited to a list of PC, folder and file activity for the current and previous day. For example, Figure 4 shows a report of activity generated as I worked on various files in one of the folders monitored by the SonicWall CDP application.
Figure 4: File summary screen
At the heart of SonicWall's CDP product line is the software, originally developed by Lasso Logic and acquired by SonicWall in 2005. There are four applications included with the CDP 110 appliance: the SonicWall CDP Agent Tool; Enterprise Manager; and Local Archive Restoration application. The fourth application is Acronis’ Bare Metal Recovery software, provided with a single Workstation license for the CDP 110. A server version of the Bare Metal Recovery software is also available.
The SonicWall CDP Agent software is installed on each client PC and is used to configure and perform the continuous backups. I had no problem installing the software on both Windows XP and Vista PCs.
In my review of the 2440i, I reported SonicWall was coming out with a Linux version for the CDP Agent at the end of 2007. Sure enough, the CDP 110 now has a Linux version of the Agent application that will run on 32 bit versions of Fedora 6 and 10, Red Hat 5.2, Suse 11.1, and Debian 4.0.
I tried installing the Linux CDP agent on Debian-based Ubuntu 9.04 Linux but failed. So, I stuck to the specs and installed the Linux CDP agent on Fedora 10, which succeeded. SonicWall's Linux installation instructions were a bit sketchy, providing incorrect commands such as tar -xvfz <filename> when it should say tar -xvzf <filename> and leaving out key details such as which directory the menu application is located, but I managed through these hurdles and got it working.
The software interface for the Linux CDP Agent is command line based (Figure 5). But if you're using a Linux machine, you're probably familiar with command line operations anyway. Using the Agent, I defined the folders to be backed up and was able to verify through the Enterprise tool running on a Windows PC that my Linux files were indeed saved on the CDP.
Figure 5: CDP Agent command line interface
Unfortunately, the CDP still does not support the Mac OS, which I think is a missed opportunity. The SonicWall Agent GUI has a clean interface and is user friendly, which is consistent with Apple's OS and image. The Mac OS can run some Linux applications, so it seems like a Mac solution wouldn’t be that difficult.
In the background, the Agent Service is running all the time, monitoring file activity on the folders and applications you specify. If you're mobile, the CDP Agent is smart enough to track file changes that have occurred while you're unable to connect to the CDP, and will back up all those changes the next time you're on your network.
Backup activity can occur even over a VPN connection, enabling continuous data protection for mobile workers. I was able to validate this over a VPN connection to an FVS318G router in my lab. The SonicWall status screen in Figure 6 shows file backup activity from my PC to the CDP appliance even though I'm on a VPN instead of locally connected.
Figure 6: Agent status
The Agent application has a simple interface for configuring backups of Folders, Applications, and checking File Activity status. Default folders for file backups include the Windows Desktop, Documents and Favorites folders. Note that only files and folders on local hard drives can be backed up, files and folders on removable media or network drives cannot be backed up by the Agent.
It is also important to note that if end users have created custom folders where they save data on their PC, those folders need to be a sub-folder of Desktop, Documents, or Favorites, or manually specified in the Agent or Enterprise tool to ensure they are backed up. I found adding new folders for backup is via simple point and click.