W. Curtis Preston
Your data center's backup needs might be able to be met by an open-source backup software package, possibly saving you quite a bit of money and giving you greater control over its functionality.
While open-source data backup software has become quite popular in some companies, if you are familiar with the likes of EMC Corp. NetWorker, IBM Corp. Tivoli Storage Manager (TSM) and Symantec Corp. Veritas NetBackup, you will find many things that your commercial package does that an open-source package cannot do, but you really should not be comparing them on a feature-by-feature basis. You should be looking at what you truly need, and seeing if these packages can meet those needs.
One of the biggest reasons that some are interested in open-source backup software is that they have access to the code. This allows them to bend the product in ways they could not do with a commercial package, and that may be the single biggest advantage to the product for them. Other people may want the product to "just work," and may find themselves tinkering with it more than they would like. Just be aware of the costs and ongoing maintenance issues associated with any custom work. After considering these costs and maintenance issues, some may continue to use more "mainstream" packages that leave these problems up to the vendor.
Let's take a look at a few open-source backup software packages. All of these provide support for Unix, Linux, Windows, and Mac OS, although to varying degrees.
Amanda is the oldest of the open-source backup software packages. It gets its name from the University of Maryland where it was originally conceived. Amanda stands for the Advanced Maryland Disk Archiver.
On one level, Amanda is a scheduling, automation, and tracking program wrapped around native backup tools like tar (for Unix/Linux) and zip (for Windows). The database that tracks all backups allows you to restore any file from any previous version of that file that was backed up by Amanda.
This reliance on native backup tools comes with advantages and disadvantages. The biggest advantage, of course, is that you will never have a problem reading an Amanda tape on any platform. The formats Amanda uses is easily available on any open-systems platform. The biggest disadvantage is that some of these tools have limitations (e.g., path length) and Amanda will inherit those limitations.
On another level, Amanda is a sophisticated program that has a number of enterprise-level features, like how it automatically determines when to run your full backups, instead of having you schedule them. It's also the only open-source package to have database agents for SQL Server, Exchange, SharePoint, Oracle, and the only backup package to have an agent for MySQL and Ingress.
Amanda is now backed by Zmanda, and this company has put the development of Amanda into overdrive. In just a few months after beginning operations, Zmanda has addressed major limitations in the product that had been there for years, and since then have been responsible for the development of a lot of functionality, including those database agents. (It doesn't hurt that the product manager used to manager the NetWorker product line.)
You have a choice of downloading the community (i.e., free) version of Amanda, or obtaining commercial support via one of Zmanda's subscription programs. If you use the community version, there is a huge community of Amanda users ready to help you.
Bacula was originally written by Kern Sibbald. Bacula went a very different direction than Amanda, choosing to write a custom backup format designed to overcome the limitations of the native tools. Kern's original goal was to write a tool that could take the place of the enterprise tools he saw in the data center.
Bacula also has scheduling, automation and tracking of all backups performed by the product, allowing you to easily restore any file (or files) from any previous version. Like Amanda, it also has media management features that allow you to use automated tape libraries and perform disk-to-disk backups.
As of this writing, Bacula is only a file backup product and does not provide any database agents. You can shut a database down and back up its files, but this is not a viable backup method for some databases.
Commercial support for Bacula is provided by Bacula Systems. Bacula Systems offers installation and technical support via subscriptions, although it does not appear it is having the same effect on the development of Bacula that Zmanda is on Amanda. Where Zmanda has released several major updates and fixes to the product, such as tape-spanning and database support, Bacula appears to have roughly the same functionality today as it did when Bacula Systems came into play.
Both Amanda and Bacula feel and behave like traditional backup products. They have support for both disk and tape, scheduled full and incremental backups, and they put those backups into a "backup format" (e.g., tar). BackupPC, on the other hand, is a disk-only backup tool that performs incremental forever backups, and stores those backups in their native format in a snapshot-like tree structure that is available via a GUI. Like Bacula, it's a file-only backup tool and it's incremental nature would be hampered by backing up large database files. However, it's a really interesting alternative for file data.
BackupPC's single most impressive feature is that it does file-level deduplication. If you have a file duplicated anywhere in your environment, it will find that duplicate and replace it with a link to the other file.
BackupPC does not have commercial support yet, but Zmanda has announced that they will be bringing it into the fold. They've even reserved backuppc.com for that purpose.
Which one should you get?
Any author that tries to explain that in an article of this scope is a crazy one, so that won't happen here. If you want the least proprietary backup format, you'd choose BackupPC. If database agents are a big driver, you'd choose Amanda. If you want the product most designed like a typical commercial backup application, you'd choose Bacula. Amanda and BackupPC require a Linux server to control your backups, where Bacula does have a Windows version of their server -- although it's not supported by Bacula Systems yet.
All three products are very popular; both Amanda and Bacula advertise themselves as the most popular open-source backup product. How is that possible? Let's take a look at the numbers. Alexa.com tracks and reports traffic for all Internet sites, and it shows that zmanda.com has a page ranking of 69K, meaning it is in the top 100K of sites on the internet based on traffic. That's pretty impressive, given that they only went into business a few years ago. By contrast, Bacula.org, Amanda.org, and Baculaysstems.org have rankings of 140K, 666K and 2.1M, respectively. This traffic is indicative of the level of interest that these products have in the overall community, but doesn't necessarily tell you how many people have installed it. To get an idea of how many people have downloaded it, we can look at SourceForge, where you will find rankings that show Bacula way out front with a ranking of 686, Amanda with 8,727, and BackupPC with 8,660. The problem with this ranking is that it only tracks downloads that come through SourceForge, and both Amanda and BackupPC are available as downloads from Zmanda.com. All of them also have a very active user community. The mailings lists for Amanda, Bacula, and BackupPC have 18K, 49K, and 19K messages, respectively.
The really nice thing about all three products is that you can download a free version and try it before you decide if you want to buy commercial support. That sounds like a good plan.
W. Curtis Preston (a.k.a. "Mr. Backup"), Executive Editor and Independent Backup Expert, has been singularly focused on data backup and recovery for more than 15 years. From starting as a backup admin at a $35 billion dollar credit card company to being one of the most sought-after consultants, writers and speakers in this space, it's hard to find someone more focused on recovering lost data. He is the webmaster of BackupCentral.com, the author of hundreds of articles, and the books "Backup and Recovery" and "Using SANs and NAS."