White Paper
Tiered Data Protection and Recovery
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Power grid failure. Powerful hurricanes. Widespread flooding. Earthquakes. Highway closures. Wildfires out of control. Intentional acts of sabotage and destruction. What do all these disasters have in
common? They are all unexpected, catastrophic events that wreak havoc on the ability of organizations to conduct normal business, especially when it comes to accessing their electronic data. In this era of continuous, instantaneous communication between organizations and their stakeholders—customers, suppliers, shareholders, employees, even governmental and regulatory bodies—being able to recover rapidly and completely from a disaster is not merely nice to have, but is a necessity.
Disaster Recovery Planning Is Essential
Whether the organization is a commercial business, government agency, healthcare provider, or educational institution, it must ensure that it is prepared for when—not if—disaster strikes. A protracted interruption in an organization’s ability to access data will disrupt daily operations. This can lead to the loss of customers and revenue or services provided to citizens, a drop in share price, or possible noncompliance fines or even jail time for failing to protect and/or provide information promptly when required. As Fig. 1 illustrates, the revenue loss for some businesses is over half a million dollars an hour. If the organization is a federal, state, or local government entity, a loss of data or access to it can be critical to e-government infrastructures and services.
In the worst case, studies have shown that if the business is not able to resume operations within ten days, the likelihood that the business will fail is extremely high (Storage Networking Industry
Association, 2002). Healthcare organizations run an especially high risk: losing access to data can lead to improper patient treatment, which can result in illness or injury—even death.
Today’s Solutions for Data Protection and Recovery
Today’s solutions for data protection and recovery (DR) are often characterized by their ability to meet three objectives: a recovery point objective (RPO), recovery time objective (RTO), and budget objective. Fig. 2 helps illustrate these concepts and defines three points in time.
• T0 is the time at which the saved data is known with confidence to be correct. T0 is the recovery point and represents the state to which the data reverts after recovery.
• T1 is the time at which the disaster occurs. The interval between T0 and T1 is the data-loss window. The RPO corresponds to the size of the
window. The smaller the data loss window, the better.
• T2 is the time at which the data has been completely recovered. The interval between T1 and T2 is the recovery time, or the length of time the system is down. The RTO
corresponds to the length of the downtime. The shorter the downtime, the better.
Fig. 1. Revenue loss for some businesses is over half a million dollars an hour. (Merrill, 2001)
Fig. 2. The relationship between a recovery point, a disaster, and recovery time.
Table of Contents
Disaster Recovery Planning Is Essential . . . .1 Today’s Solutions for Data Protection and Recovery . .1 The Data Protection and Recovery Storage Solution Dilemma . . . .3 Xiotech’s Tiered Data Protection and Recovery Storage Framework . . . . .3 How it Works in Practice . .5 Summary . . . .7 Sources . . . .7 Appendix: Disaster Recovery Service Tiers . . . .8
Business Type Revenue Loss (per hour)
Enterprise Resource Planning $780,000
Electronic Commerce $600,000
Supply Chain Management $660,000
Internet Banking $420,000
POS/EFT $210,000
Customer Service Center $222,000
Tiered Disaster Recovery Pg 2
Finally, budget is the means by which an organization can reduce its RTO and RPO windows—more money, smaller window. This may be achieved through the acquisition and implementation of some or all combinations of additional resources, such as storage, server, network, and personnel.The Seven Tiers of Disaster Recovery Service
Solutions for DR are commonly explained in terms of seven tiers of service. These tiers range from Service Tier 0, which employs no DR solution at all, to Service Tier 6, which implements a completely integrated software and hardware solution that achieves nearly zero data loss. These service tiers are described briefly below. For more detail, see the appendix to this paper.
Service Tier 1 is informally known as the Pickup Truck Access Method (PTAM). It consists of using traditional backup software to copy data to tape and storing the tape off site, typically by loading a truck with dozens or even hundreds of tape cartridges. If a disaster occurs, the data is once again loaded on a truck, delivered to a designated facility, and restored from tape back onto disk. In most situations, this solution requires purchasing and deploying equipment for a completely new data center.Service Tier 2 consists of using PTAM plus a hot site, where the necessary hardware and software have already been installed and configured.Service Tier 3, known as electronic vaulting, also relies on backing up data, but differs from the first two service tiers in that backups are transported electronically to a hot site.
These three service tiers share several disadvantages. The most important is that they all rely on backup copies of the data, which are in a specific format, as written by the backup software. As a result, if an organization using one of these approaches suffers a disaster and has to implement its recovery plan, it will lose all the updates that have occurred since the backup was made, resulting in a large data-loss window. Another similarity between these solutions is that they typically rely on less-costly forms of storage media, such as tape, which has been found by several industry research organizations to fail on restore as much as 30 percent of the time. Finally, Service Tiers 2 and 3 make use of a hot site, at which dedicated hardware and software is used only in the event of a disaster. The rest of the time it sits idle, a waste of valuable computational and storage resources.
Service Tier 4 consists of two active sites, where each acts as a backup site to the other. One version consists of backing up data and transporting the backups electronically to the other site. The other version consists of replicating data.Service Tier 5 also consists of two active sites. The difference between Service Tier 5 and Service Tier 4 is that, for selected data, an update is not recorded as complete until both sites have completed the update.Service Tier 6 consists of two active sites with network switching, which immediately and automatically transfers one site’s workload to the other site when a disaster occurs.
Service Tiers 4 through 6 offer superior RTO and RPO characteristics over the lower service tiers. However, the solutions from the higher tiers are more costly and more complex to plan and implement.
No DR Plan All Data Lost
0
PTAM 24-48 Hours
1
PTAM & Warm Site 24-48 Hours
2
Electronic Vaulting Warm Site <24 hours3
Hot Active 2nd Site Seconds
4
2nd Site, 2-Phase Commit Seconds
5
Zero Data Loss None
6
The Data Protection and Recovery Storage Solution Dilemma
Many vendors offer solutions that correspond to one or more of the service tiers described above. Most of the available solutions, however, fit only one of two categories:
• Glass-house solutions. These solutions typically require a large, highly trained IT team that has
specialized experience in DR, with dedicated DR computation, network, and storage resources. These solutions are extremely costly and complex to acquire, install, train, and use, requiring extensive professional service support. These solutions deliver small RTO/RPO windows but with high cost of acquisition and operation.
• PTAM solutions. These solutions allow for reduced costs relative to Glass-House solutions but
with large RTO/RPO windows. Even though these solutions are less costly to acquire and install, they tend to be labor intensive and time consuming, often requiring staff to work long overtime hours and postpone other critical enterprise tasks.
The challenge many organizations face is they require small RTO/RPO with low cost and ease of use. They want to leverage their existing staff without increasing their budget. They would like to implement DR storage resources but utilize them for production as well to optimize their investment.
Furthermore, in the face of a geographic disaster, who will recover the business’s critical systems? Ease of use becomes imperative to those organizations that want their businesses “back up and running” quickly but do not have the trained technical staff to recover outside the local geographic area.
What these organizations demand is a simplified, yet powerful, DR storage solution that has low acquisition and operating cost with increased production potential. Such a solution does not require expensive, complex hardware, software, or professional services to implement, train, and use. This solution provides the best of glass-house solutions with the lower cost of PTAM solutions. These organizations need reconfigurable, easy-to-use DR solutions that provide a variety of choices and do not overburden an already overworked staff.
Xiotech’s Tiered Data Protection and Recovery Storage Framework
Xiotech Corporation’s Tiered Data Protection and Recovery Storage Framework satisfies the rapidly escalating need for a simplified, yet powerful, data protection architecture that offers integrated solutions in a variety of shapes and sizes. Xiotech has accomplished this because it practices two fundamental principles. First, Xiotech’s products and services are designed to be easy to use. Second, Xiotech’s products and services are developed along a continuum.
With this framework, an organization can deploy the storage system that meets its needs today and grow the system seamlessly as its requirements change and budget allows. When the organization needs to protect its enterprises against disaster, it purchase only the components necessary to reassemble its existing configuration into a DR solution.
This easy, integrated approach is enabled by software that is architected from the ground up to mask complexity and allow greater scalability and functionality at a lower cost than traditional solutions. Unlike other offerings from traditional storage vendors, this is not a legacy or “7th-generation” architecture cobbled together with acquired software of innumerable generations from different vendors and made to “look” simple with a GUI. In addition, this is not a 7th-generation
Tiered Disaster Recovery Pg 4
architecture with disparate software that can only be configured and implemented properly with expensive professional services.With Xiotech solutions, organizations always easily build on what they have already implemented. Organizations never purchase anything they do not need, and they never have to dispose of anything they have purchased. This is complete investment protection.
Xiotech gives organizations the power to grow their storage solutions seamlessly, transparently, and incrementally, by letting them build their solutions one building block at a time. Organizations purchase only the components they need when they need them and add them to what they have already implemented without ever impacting critical enterprise applications. And as organizations build on their solutions, value grows—in direct proportion to the money invested.
Xiotech’s vision makes the Xiotech Tiered Data Protection and Recovery Storage Framework easy to manage, powerful, and flexible. But it doesn’t stop there. Instead of six disparate service tiers that employ divergent technologies, the Xiotech framework provides four simple recovery tiers that employ integrated hardware and software solutions, offering an array of choices in terms of cost, capacity, and performance. Each solution is built from a set of fundamental building blocks that allow organizations to scale up and down the tiers—and horizontally across other Xiotech frameworks—without planned downtime, while protecting their investments. These building blocks include powerful replication software, sophisticated appliances, and Magnitude 3D®storage systems.
Xiotech’s Tiered Data Protection and Recovery Storage Framework integrates these solutions with the following tiers:
• Instant Recovery Tier. Solutions from this tier are most appropriate for mission-critical data.
These solutions employ synchronous replication techniques to achieve nearly instantaneous data recovery. Xiotech’s Instant Recovery Tier is analogous to Service Tiers 5 and 6.
• Rapid Recovery Tier. Solutions from this tier are appropriate for mission-critical and
business-vital data. These solutions employ asynchronous replication techniques to achieve rapid data recovery. Xiotech’s Rapid Recovery Tier is analogous to Service Tiers 4 and 5.
• Fast Recovery Tier. Solutions from this tier are best for data that is important for business. These
solutions employ asynchronous or scheduled synchronous replication to achieve fast data recovery. Xiotech’s Fast Recovery Tier is analogous to Service Tiers 3 and 4.
• Standard Recovery Tier. Solutions from this tier work well for data that is important either for
general business use or for sustained productivity. These solutions may employ tape backup methodologies, or asynchronous or scheduled synchronous replication to achieve standard data recovery. Xiotech’s
Standard Recovery Tier is analogous to Service Tiers 2 and 3.
Xiotech’s Tiered Data Protection and Recovery Storage Framework is summarized in Fig. 5. Mission Critical (99.999%) Mission Critical (99.999%) to Business Vital (99.99%) Business Important (99.9%) Business Important (99.9%) to Important for Productivity
(99%) Instant Recovery (Hot Site)
• Synchronous Replication
Rapid Recovery (Hot Site) • Asynchronous Replication
Fast Recovery (Warm Site) • Asynchronous Replication or • Scheduled Synchronous Replication
Standard Recovery (Cold Site) • Scheduled Synchronous Replication
Solution Tiers Data Requirements
Magnitude 3D Storage Systems and Information Lifecycle Management
Information lifecycle management (ILM) involves managing information across its useful life—from creation to disposal. The guiding principle of ILM is that the cost of storage media should be aligned with the business value of the information stored. This is embodied in Xiotech’s integrated framework solutions from Tiered Storage to Tiered Data Protection and Recovery. All these frameworks
incorporate ease of use and flexible storage with Magnitude 3D storage systems.
Magnitude 3D storage clusters can be configured easily, without restriction, with drives from three storage classes to suit the organization’s needs.Enterprise Fibre Channel drives are used for mission-critical applications, such as online transaction processing (OLTP), enterprise messaging, and decision support, where performance, reliability, and availability are essential.Economy Enterprise Fibre Channel drives are used for business-vital applications, such as file serving, application development, and data warehousing, where reliability and availability are still indispensable, but performance is less critical and acquisition cost may become an issue due to the large volumes of data.Economy Serial Advanced Technology Attachment (SATA) drives are used for applications with infrequent read/write activity, such as archiving, bulk storage, and disk-to-disk backups, where availability and performance are less important and lower cost is desirable.
Xiotech also incorporates two additional storage tiers in its ILM offerings: massive array of idle disks (MAID) systems and Spectra Logic®tape libraries. MAID is used for long-term repository storage of
data that may need to be retrieved quickly at some point. It provides a cost-effective alternative to tape, while maintaining the fast, easy data access of disk storage systems.
Data stored on any of these tiers can be copied or backed up to tape for off-site storage to protect against complete data center disasters or wide-ranging natural events.
How it Works in Practice
The following example illustrates the scalability and configurability of the Xiotech Tiered Data Protection and Recovery Storage
Framework. The IT team of General Hospital in Eden Prairie, Minnesota, to comply with Health Insurance Portability and Accountability Act (HIPAA) requirements, purchases and installs a Magnitude 3D 3000e Edge storage system in March 2005. This system, Zumbro, has one controller and is configured with two drive
bays populated with Economy Enterprise Fibre Channel drives. In the fall of 2005, General Hospital completes construction of a clinic several blocks away, close enough to support a Fibre Channel connection. The CIO increases the IT budget and instructs the IT team to implement a DR solution. In March 2006, as part of that implementation, the hospital deploys a Xiotech Fast Recovery solution, which includes
upgrading Zumbro to a
Magnitude 3D 3000s clustered system, installing a new Magnitude 3D 3000e Edge system, Kettle, at the
clinic, and implementing synchronous data mirroring between the two sites using Xiotech’s DataScale™ Geo-Replication software (Fig. 7).Zumbro is the
primary site, and Kettle is
the warm secondary site.
Fig. 6. Zumbro, a Magnitude 3D 3000 Edge storage system installed at General Hospital.
Tiered Disaster Recovery Pg 6
Demand for services at thehospital and clinic grows, so in March 2007, another controller node is
purchased for Kettle,
making it a storage cluster.
Kettle is now more resilient
to failure, and will be better equipped to take over
Zumbro’s workload if
necessary. At the same time, more capacity is added to Kettle and Zumbro.
Late in 2007, the hospital upgrades to Xiotech’s Rapid Recovery storage solution and makes the clinic a hot site. New clustering software is purchased for the hospital’s applications, as well as servers for the clinic. Because there is enough capacity, no additional components need to be purchased from Xiotech. In February 2008, General Hospital acquires a new clinic located approximately 30 miles away. Another Fast Recovery storage solution is purchased from Xiotech. It includes a Magnitude 3D 3000e Edge storage system, Vermilion,
equipped with Economy SATA drives and two TimeScale™ appliances that work together to execute synchronous, asynchronous, and snapshot replication. One appliance is installed at the
hospital and one is installed at the newly acquired clinic.
In January 2009, the hospital upgrades to a Xiotech Instant Recovery solution, which includes more powerful replication software.
Notice that throughout this scenario the organization is always building and adding to its data
protection and recovery storage capabilities. At no time does it have to discard any of the hardware or software components that it previously purchased.
Fig. 8. Kettle is now a two-controller cluster; both Kettle and Zumbro have more storage capacity.
Summary
A great divide exists in today’s data protection and recovery solutions. In theory, a wide variety of solutions, from PTAM to dual-active sites, are possible. In practice, however, most solutions are developed at two ends of the spectrum, one around PTAM offerings for modest budgets and the other around glass-house offerings for small RTO/RPO windows. No solutions are available to meet the needs of enterprises that fall in the middle of the spectrum. These organizations need and demand small RTO/RPO windows with low cost and simplicity. They want to leverage their existing staff without increasing their budget. They want to implement DR storage resources but utilize them for production as well.
Xiotech fills this gap with its unique vision of a Tiered Data Protection and Recovery Storage
Framework that is based on the essential ideas of ease of use and a product continuum. Each solution in Xiotech’s framework is assembled from a set of fundamental building blocks, which can be
reassembled, augmented, and reconfigured to implement a more powerful solution when necessary. The result is a set of powerful, easy-to-use data protection and recovery storage solutions that can be seamlessly and transparently scaled and customized as the organization grows and its needs change. With Xiotech, organizations can be confident that they will not be stuck with a one-size-fits-none solution with only a costly way out.
Sources
Baker, E; Van Hise, G; Luko, S. 1997. Performance Hierarchy of Disaster Recovery Solutions.Disaster Recovery Journal 10(3).
Merrill, David. 2001. Developing Return on Investment and Business Case Support for Storage Area Networks.RBC Capital Markets.
Tiered Disaster Recovery Pg 8
Appendix: Disaster Recovery Service Tiers
In 1993, the SHARE Technical Steering Committee published a white paper that described seven tiers of service for disaster recovery (DR). These seven tiers are commonly used to describe solutions for DR and are described in detail below.
Service Tier 0: No Off-Site Storage of Data
The Service Tier 0 approach consists of a lack of a DR solution. Nearly all organizations using this approach back up their data but store the backups on site, unlike the other six true DR solutions, in which backups are stored off site. If a catastrophic event occurs, such organizations may be able to restore their data from backup—as long as the damage caused by the disaster does not also prevent access to the backups. Natural disasters or intentional acts of destruction are usually not so selective in their effects, however. It is much more likely that an entire building or even several city blocks or more are affected; few disasters target a single floor of a building and leave the others undamaged.
Service Tier 1: Pickup Truck Access Method
The Pickup Truck Access Method (PTAM) is not, strictly speaking, a DR solution. It is a commonly used practice for protecting data that has been applied to the problem of DR. PTAM consists of backing up data, most often to tape, although any easily transportable storage media will do, and then physically transporting the backup media to a different location for storage. When the data is needed, it is transported to a cold site, which has the infrastructure necessary to support servers, storage, and networks, and only then is the hardware purchased and installed. One advantage of this solution is its relative low cost—if no disaster occurs. The down side, however, is that if disaster strikes, establishing a new data center at the cold site will take considerable time, money, and labor. Another disadvantage is the impracticality of testing this solution.
Service Tier 2: PTAM Plus Hot Site
Like Service Tier 1, the Service Tier 2 solution consists of backing up data to portable storage media and then physically transporting the media to an alternate location. The difference is that when the data is needed, it is transported to a hot site, where the hardware is already up and running. Advan-tages over the previous solution include a much shorter recovery time and the ability to test the method before a disaster happens. In addition, compared to the solutions represented by the higher service tiers, the Service Tier 2 solution is still relatively low cost.
Service Tier 3: Electronic Vaulting
Like Service Tiers 1 and 2, the first part of this method consists of backing up the data. Unlike the previous solutions, however, in which the media containing the backup data is transported physically, electronic vaulting transports the data electronically to the hot site. This reduces the amount of time needed to transport the data, resulting in faster recovery time. Savings in physical transportation costs are also achieved. These savings, however, are more than offset by the cost of the telecommunication lines that are now required between the data center and the hot site. These disadvantages and several other key characteristics of these solutions are summarized in Fig. 11 below.
Service Tier Type Often Used Reli-ability Storage Media RPO Complete-ness Data Loss Window RTO Avail-ability Downtime Cost Ease of Use Labor Required (Recover) Test-ability
Tier 1 Tape Poor Low High High None Day+ Poor Week+ Poor
Tier 2 Tape Poor Day+ Poor to
Good Day+ Poor
Low to
Moderate High High Moderate
Tier 3 Tape Poor < Day Poor to
Good < Day
Poor to Moderate
Moderate High High Moderate
Solution
Service Tier 4: Two Active Sites
A Service Tier 4 solution can address the disadvantages of solutions from Service Tiers 1 through 3. A Service Tier 4 solution consists of two active sites, where each acts as a backup site to the other. One requirement for this solution is that the sites should be at some distance from each other to ensure that the same disaster will not put both of them out of commission. In addition, each site must have enough unused processing capacity that it can absorb the other site’s workload if need be.
This solution has two variations. The first variation is similar to electronic vaulting, in that data is backed up and transmitted electronically from each site to the other. The major difference between the Service Tier 3 and Service Tier 4 solutions is whether the second site is active or idle. The second variation replicates data, either through continuous transmission of data or through dual online storage. The use of replication in the second variation significantly shrinks the size of the data-loss window, and consequently improves the completeness of the recovery. With an automatic network-switching
capability, a Service Tier 4 solution can reduce data recovery to hours or even minutes.
Service Tier 5: Two Active Sites with Two-Phase Commit
As with Service Tier 4, the Service Tier 5 solution consists of two active sites, each with enough unused processing capacity that it can take on the other’s workload if disaster strikes. The difference is that, for selected data, when an application initiates a request to update the data, the application is not notified that the update is complete until both sites have concluded the update operation. Organiza-tions using this solution can only lose data that is in the process of being updated. One disadvantage of this solution is that it increases the time required to update data, since the application has to wait for the update request and acknowledgement to be transmitted to the remote site.
Service Tier 6: Zero Data Loss
As with the Service Tier 4 and 5 solutions, a Service Tier 6 solution consists of two active sites, each with enough unused processing capacity that it can take on the other’s workload in the event of a disaster. The difference is that a Service Tier 6 solution immediately and automatically transfers one site’s workload to the second site when a disaster occurs. This solution requires dual online storage and an automatic network-switching capability. One disadvantage of this solution is that its high cost quite often leads to increased complexity. The reason for this is that if an organization implements a Service Tier 6 solution, the organization will usually only use that solution for its business-critical data. Less costly solutions from lower service tiers will be employed for less critical data. Using solutions from several different service tiers, however, increases the complexity in planning and implementing disaster recovery. These and several other key characteristics are summarized in Fig. 12 below.
Service Tier Type Often Used Reli-ability Storage Media RPO Complete-ness Data Loss Window RTO Avail-ability Downtime Cost Ease of Use Labor Required (Recover) Test-ability Tier 4 FC Drives Very High Secs Moderate to Good Mins Moderate to Good
High Low Moderate
to Low Good
Tier 5 FC
Drives Very
High High Low Low Good Secs Good Secs Good
Tier 6 FC
Drives Very
High None Excellent Secs Excellent
Very
High Low Very Low Excellent
Solution
