The fundamental benefit of true continuous data protection (CDP) is the preservation of revenue-generating, or revenue-enabling, business applications. The promise of CDP is the instant availability of business applications despite any failure, for local or remote recovery. For years, tape backup was considered the only means of data protection and recovery. In and of itself, tape backup is a relatively reliable and affordable data protection method. Tape media is durable and can be easily stored in a climate-controlled environment for long-term protection.
However, as data volumes have grown and dependence on data availability and fast recovery has increased, the limitations of tape media have become all too apparent.
For starters, data recovery from tape is time-consuming and imprecise. Recovery points can exceed 24 hours, and restoring an application to full operation can take even longer. This makes it difficult for companies to meet Recovery Point Objectives (RPOs) and service-level agreements (SLAs).
When tapes are stored off-site, as is often the case, it can take several days to retrieve the tapes and restore data. The revenue and productivity lost during that period can be devastating to a business.
Most tape backup implementations use backup agents on application host servers to back up data from servers. These agents consume application host processing time, which becomes problematic (especially when virtual server technology is used). In some cases, server backup can impact the server itself-enough to affect application performance. Furthermore, the explosive growth of data has expanded server backup requirements to the point where the backup window has diminished, and completing backups on time has become nearly impossible.
Array-Based Data Protection
Array-based data protection
Some organizations have opted to replicate to array-based disk mirror or snapshot volumes at a disaster recovery (DR) site in order to speed up data recovery. Array-based snapshots improve recovery points by retaining more frequent data changes between backups. However, because most disk arrays do not communicate across vendor barriers, array-based replication requires a dedicated, homogenous infrastructure at both the primary and DR sites-a major drawback. In addition to creating vendor lock-in, array-based replication consumes a great deal of network bandwidth.
Failover processes between sites can be complex and error-prone, and failback processes are often insufficiently planned or go untested. For these reasons, replication is usually limited to Tier 1 storage, while Tier 2 and Tier 3 storage data remains unprotected and prone to loss or corruption.
Lastly, the integrity of array-based snapshot recovery points is usually limited to the last good snapshot (which could be several hours behind).
CDP technology brings it all together
The CDP concept has emerged as a way to better protect data and improve its recoverability, leveraging disk-based data protection to enhance the effectiveness of tape backup. By offering continuous journaling, CDP technology protects data for a much longer period of time than tape backup, reducing the required frequency of tape backups. CDP provides the capability to replicate and maintain multiple versions of data at local and remote DR sites for online data retention and recovery to any known good point in time.
When used properly, CDP technology can unify local and remote data protection processes, combining replication and backup into a comprehensive solution that minimizes data loss, speeds recovery, and reduces or eliminates the need for tape-based data protection.
Reduced Backup Window and Storage Footprint
Reduced backup window and storage footprint
CDP technology enables organizations to replace daily tape backup with periodic disk replication over IP or Fibre Channel. This reduces tape backup requirements from daily to weekly-or even longer. In doing so, CDP technology can eliminate hundreds of daily tape backups per year.
Because tape backups can be scheduled at any time, organizations are no longer restricted by limited backup windows. In addition, companies can reduce or eliminate the usage of large physical tape libraries in the data center, which reduces storage overhead and frees up physical space.
For instance, a leading pharmaceutical manufacturer used tape to protect sensitive data stored in its ERP system. Although it assumed the tapes would be durable, the IT staff found itself dealing with numerous hardware and media failures, which impacted backup jobs and cost a great deal of time and money. To make matters worse, it was difficult to validate the integrity of the backup data, and data was growing to the point where the IT team could not complete backups within its limited timeframe.
Since installing a CDP solution, including a virtual appliance that integrates with the company’s VMware ESX Server environment, the firm now only uses tape for weekly, monthly and yearly backups. This has enabled the company to save money on tape and associated management costs, and has reduced its RPO from one day to one hour.
Highly Reliable, Low-Cost Disaster Recovery
Highly reliable, low-cost DR
CDP helps reduce capital expenditures (CAPEX) by eliminating the need for array-based software licenses, and helps lower operating expenditures (OPEX) by reducing the frequency of tape backups.
The most effective CDP solutions can replicate data across system, protocol and virtual and physical boundaries. This eliminates vendor lock-in and allows organizations to use existing or more efficient storage.
When a NY-based financial institution needed to protect data on a limited budged and IT staff, it turned to CDP technology. Stringent government regulations required off-site data archiving and retention. As the company began to expand, it became increasingly difficult to store data and ensure its integrity and availability. They used servers with direct-attached storage (DAS) for daily disk-to-disk (D2D) backup, and the data volume was becoming overwhelming. Connectivity bandwidth was no longer adequate, backup windows were shrinking, and the risk of unprotected data was growing.
Implementing CDP technology enabled the company to virtualize existing data sets and create a centralized storage array. This preserved the company’s DAS configuration, while improving data security and protection. If necessary, the IT team can now access and recover data from anywhere (without requiring a technician to be on hand), simply by mounting a snapshot. This principle also holds true for testing, scheduled maintenance, and upgrades.
Having continuous protection from a single, centralized point of control has increased operational efficiency. And the cost savings have strengthened the company’s bottom line. These savings are a direct result of reduced data volumes, minimized bandwidth requirements, and the ability to leverage existing intellectual property (IP) and storage infrastructures-without requiring complex new technologies or processes.
Because data is stored on disk, CDP provides significantly faster recovery times than tape. Files, databases, mail stores and entire systems can be recovered within minutes rather than hours. With some CDP solutions, entire sites can be brought online in approximately 30 minutes, rather than several days.
A multidisciplinary engineering firm experienced this firsthand. The company needed to deal with growing data stores, while ensuring adequate protection and access to all of the file-level, Microsoft Exchange Server, and Microsoft SQL Server data. The company’s distributed office structure made this difficult. Data protection was originally limited to local tape backups. Daily differential and full weekly tape backups were handled by non-IT individuals in each office. As a result, the IT team spent a significant amount of time troubleshooting problems.
CDP was the answer. The company implemented a CDP solution, setting it up to perform hourly backups. All data from remote offices is written to a set of tapes at the headquarters and taken off-site for archiving. Compression and data reduction technology eliminate duplicate data, which improves replication efficiency and reduces bandwidth requirements. Now the company can keep as much as 18 months of snapshots in each office. The IT staff can now recover data from disk in five minutes, and spends much less time dealing with tape and backup administration.
The full value of CDP became even clearer when a hurricane struck, leaving one office without power for multiple days. Members of the IT team-some of whom had little experience with the system-were able to mount replicas as live volumes from a CDP appliance at headquarters and redirect user traffic there, minimizing the total downtime to just 30 minutes. When power was restored, the team was able to replicate the data back and switch over to the local servers without users noticing.
Not All CDP Solutions Are Created Equal
Not all CDP solutions are created equal
When choosing a CDP solution, it is important to consider your organization’s business needs and objectives to ascertain which product will provide the highest business value. If cost is an issue, you need a solution that integrates with your existing infrastructure.
You need it to offer offer centralized management and reporting to reduce management overhead. Compression and data reduction minimizes storage requirements, allowing you to store more data with less hardware.
If your organization struggles to meet backup windows, then backup acceleration through backup software integration is an ideal way to increase tape backup speed, while offloading processing from application servers. WAN optimization further accelerates backup by minimizing network bandwidth requirements for replication, reducing them by as much as 90 percent.
Businesses that want to improve SLAs benefit from CDP solutions that provide application-aware snapshots, which provide the fastest possible recovery with the highest possible levels of granularity. They eliminate the need to perform time-consuming bare-metal restores.
While all CDP technologies offer advantages over traditional data protection mechanisms, only the most sophisticated CDP solutions provide features that ensure instant availability of critical business applications. The more comprehensive CDP solutions enable rapid and granular recovery in all disaster scenarios to maximize the benefits of this technology.
Bobby Crouch is the Product Marketing Manager at FalconStor Software. He is a 20-year technology industry veteran, with roles ranging from development engineering to sales and marketing. Bobby’s expertise extends from microprocessor architecture, servers, networking, enterprise software and storage. He can be reached at email@example.com.