By Eric Burgener, INFOSTOR — June 4, 2008
To open source, or not to open source?
Certain organizational profiles have historically favored open source adoption. First, an organization must have technically astute IT personnel who are willing to take on the added burden of tool maintenance and, in some cases, development. Second, these organizations’ environments have tended to be less complex, and can get by without some of the advanced functionality that is available with commercial software. And third, the possibility of unreliable technical support must not cause risk to business operations.
Because technical support is basically provided by the open source community — a self-proclaimed special interest group who does not get paid for its efforts — it is inconsistent. At times it can be responsive and of high quality, at other times less so. While the same can also be said of commercial support offerings, they do at least provide an escalation path lacking in open source that can focus a vendor on resolving a problem in a timely manner. For these reasons, open source data-protection products have generally been deployed in smaller, less-complex environments for non-mission-critical applications.
In 2007, Zmanda Inc. changed the face of open source data protection. By creating a commercial backup software offering around Amanda, Zmanda promises to address the legacy issues with open source data-protection alternatives. Amanda is the only open source data-protection distribution that has this commercial backing. Zmanda calls its product Amanda Enterprise and targets it at SMEs. Generally, Amanda Enterprise licensing runs about 25% to 30% of the cost of well-known backup applications. Users familiar with commercial backup software licensing will also be pleased not only with the acquisition costs of Amanda Enterprise, but also with the simple licensing model. Included with the base subscription price are features such as support for disk-based backup, SANs, Windows VSS, compression, and encryption, as well as alternative client and server-independent restore support. Backup application agents are the only separately priced products in the Zmanda offering, and today they include Solaris, Linux, Windows, Mac, Exchange, SQL Server, and SharePoint, with Oracle and many others on the way.
Amanda’s Intelligent Scheduler
Most backup products provide a scheduler that allows administrators to set up any backup schedule they desire, but they all rely on the administrator to tell them exactly what to do and when to do it. A common concern in setting up a backup schedule is load-balancing to smooth out resource (backup server CPU, network, I/O, target devices, etc.) requirements so that peak load requirements are not much different from average load requirements. The inability to manage this effectively can result in purchasing of a lot of additional capacity that remains underutilized except for peak load conditions.
Amanda’s approach allows an administrator to specify a set of parameters within which the software will calculate the backup schedule to optimally smooth resource requirements across the days in each week. For example, instead of giving Amanda the exact instruction, “Do a full backup every Sunday for clients A, B, and C; full backups on Wednesday for clients D, E, and F; and incrementals at all other times,” the administrator sets a few parameters that define how Amanda calculates the backup schedule: “For every client, do at least one full backup within each seven-day period, and do incrementals all other days with a maximum time between full backups of seven days.” If this appears simpler with only six active clients, imagine how much simpler it is when an environment has hundreds of clients that need to be scheduled.
Amanda’s Intelligent Scheduler also provides a great solution for disconnected clients. If a client is disconnected on a particular day, the scheduler takes that into account, allows the backup to complete while skipping that client, and then makes backup scheduling adjustments (such as promoting the backup level for that client) to ensure backups of that particular client will still meet the parameters established by the administrator.
To know more about the Amanda’s Intellegent Backup Scheduler please see this presentation