Computer systems contain large amounts of information. This information includes personal information, such as financial information, customer/client/patient contact information, business information, audio/visual information, and much more. This information also includes information related to the correct operation of the computer system, such as operating system files, application files, user settings, and so on. With the increased reliance on computer systems to store critical information, the importance of protecting information has grown. Traditional storage systems receive an identification of a file to protect, and then create one or more secondary copies, such as backup files, containing the contents of the file. These secondary copies can then later be used to restore the original data should anything happen to the original data.
In corporate environments, protecting information is generally part of a routine process that information technologists perform for many computer systems within an organization. For example, a company might back up critical computing systems related to e-commerce such as databases, file servers, web servers, and so on as part of a daily, weekly, or monthly maintenance schedule. The company may also protect computing systems used by each of its employees, such as those used by an accounting department, marketing department, engineering department, and so forth.
Current storage management systems employ a number of different methods to perform storage operations on electronic data. For example, data can be stored in primary storage as a primary copy or in secondary storage as various types of secondary copies including, as a backup copy, a snapshot copy, a hierarchical storage management copy (“HSM”), as an archive copy, and as other types of copies.
A primary copy of data is generally a production copy or other “live” version of the data that a software application uses and is generally in the native format of that application. Primary copy data may be maintained in a local memory or other high-speed storage device that allows for relatively fast data access if necessary. Such primary copy data is typically intended for short term retention (e.g., several hours or days) before some or all of the data is stored as one or more secondary copies, for example to prevent loss of data in the event a problem occurred with the data stored in primary storage.
Secondary copies include point-in-time data and are typically intended for long-term retention (e.g., weeks, months or years depending on retention criteria, for example as specified in a storage policy as further described herein) before some or all of the data is moved to other storage or discarded.
Secondary copies may be indexed so users can browse and restore the data at another point in time. After certain primary copy data is backed up, a pointer or other location indicia such as a stub may be placed in the primary copy to indicate the current location of that data. One process for creating a content index and classifying data is described in U.S. patent application Ser. No. 11/564,180, which is incorporated herein by reference. Once a content index is available, client systems no longer need to be involved when searching for data and can be focused on more desirable tasks such as running production applications.
Although the content index saves client resources, the usefulness of the content index can cause the content index itself to become a resource in high demand. When the content index is relied upon for processing searches and finding data among many copies, the content index can become a single point of failure for performing these operations, and the performance of searches and other operations may suffer based on the available performance of the content index.
The foregoing examples of some existing limitations are intended to be illustrative and not exclusive. Other limitations will become apparent to those of skill in the art upon a reading of the Detailed Description below. These and other problems exist with respect to data storage management systems.
In the drawings, the same reference numbers and acronyms identify elements or acts with the same or similar functionality for ease of understanding and convenience. To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the Figure number in which that element is first introduced (e.g., element 101 is first introduced and discussed with respect to FIG. 1).