7 Technology Circle
The Future of Backup
The Ghosts of Backup Past, Present, and
Future
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Introduction
When Yogi Berra said “The future ain’t what it used to be” he could have been talking about backup rather than baseball. Despite enormous progress in backup technologies over the last decade, the “secondary” technology of backup as a whole has barely kept up when compared to the incredible gains in the “primary” technologies associated with computer and storage platforms. The fact is that backup vendors as a whole have failed to make enough progress in delivering increasing fundamental value to customers. This white paper discusses the fundamental challenges associated with backup, the past and present state of the business continuity and disaster recovery industry and technologies, and explores several data protection future scenarios.The Fundamental Challenges
Disk Capacity and Bandwidth
The most critical challenge of backup has now existed for decades - primary data is growing at a much faster rate than the bandwidth of the interconnects available for copying that data to some secondary storage location. Practically, all IT professionals understand this phenomenon. Disk drives have increased in capacity from approximately 100MB in 1990 to 2TB in 2010 - a factor of 20,000X! At the same time, interconnect technologies have evolved at a much slower rate. For example, Ethernet moved from 10Mbps in 1990 to 10Gbps in 2010 - a factor of 1000X. SCSI bandwidth increased during this time from 5MBps to 750MBps - a factor of 150X.
The chart below illustrates the gap that has developed in the last twenty years primary storage capacity on a per-disk basis and common interconnect technologies. The factors that led to this gap will continue to be in play in the next decade as well.
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Primary Versus Secondary Storage Capacity
In 1990, disk drives were approximately 100MB in capacity. Tape drives at that time were approximately 5GB in capacity. This represented a 1:50 ratio. In 2010, disk drives are 2TB in capacity while tape drives (LTO-5) are 1.5TB in capacity. This represents a 1:0.75 ratio. This diminishing capacity ratio is one of the fundamental reasons that tape-based backup is so much less viable than it was 20 years ago.
However, disk-based backup presents its own challenges. Disk-based backup has at worst a 1:1 ratio (when the same disk types are used in primary and secondary storage) and at best an approximate 1:3 ratio (when higher-speed 15K RPM drives are used.) When SSDs (Solid State Disks) drives are considered the ratio doesn’t get better - while expensive, there are 2TB SSDs available today while the largest commodity rotational drives available are 2TB.
Data Reduction Techniques and Reliability
Backup works by creating copies of data and thus increasing the overall reliability of the system being protected. It’s that simple. Data reduction, on the other hand, works by eliminating redundancy. The two work against each other.
In addition, there is a continuing drive by vendors to incorporate data reduction into primary storage. In the past, this hasn’t gained much traction because of the performance penalties associated with data reduction techniques. However, the strong venture capital and mergers and acquisition activity in this area as well as global 1000 vendors’ statements indicate a renewed interest and focus in primary storage deduplication.
What does primary storage data reduction have to do with the fundamental challenges of backup? The answer concerns primary versus secondary storage capacity ratios. When data reduction is used for secondary storage, it can lower the price per effective terabyte of backup capacity when compared to the primary storage being protected. However, when primary storage data reduction is employed it reduces the aforementioned primary versus storage capacity ratio.
Complexity and Operational Costs
The challenges previously discussed in this section are based upon the technology trends associated with storage and with backup. However, there is another fundamental challenge that users and potential users of backup have been increasingly facing - the sheer complexity of data protection and the rising operational costs due to that complexity.
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The complexity is driven primarily by several factors:• Few data protection products handle the major functions associated with backup - which include not only backup but archiving and disaster recovery - in an integrated manner. Licensing on a piecemeal basis greatly exacerbates this complexity.
• Many data protection products push the task of purchasing, assembly, integration, management, and monitoring of backup servers, networking, storage, operating system, anti-virus software, backup software, and other components back to their customers. This increases operational costs dramatically.
The Ghosts of Backup Past, Present, and Future
Now that we’ve set the stage by presenting some of the fundamental problems associated with backup, let’s discuss the past, present, and future of backup.
Past: Tape Era
“The future, according to some scientists, will be exactly like the past, only far more expensive.”
[Alan Kay]
The past of backup was dominated by tape. In order to understand this, it helps to understand how tape was perceived in the past. As we discussed in the fundamental challenges section of this paper, in 1990 the capacity of a single tape was approximately 50 times that of a single disk. Perhaps even more importantly, tape was much less expensive on a per gigabyte level than disk.
It was due to these attributes that people used tape. Because despite its popularity, tape had serious issues. (Actually, tape has serious issues continuing to today - but we’ll discuss that when we talk about “the ghost of backup present.”) One of the major issues with tape was issue of “shoe-shining” (also called “sawing”) - a situation in which the tape would start and stop because it couldn’t be written to fast enough to keep it streaming. Another major issue that emerged were alignment problems that occurred when one tape drive was used to write data and another tape drive was used to read that data.
Perhaps more importantly, tape relied upon human beings to correctly implement rotational strategies and to physically move the tapes off the premises for disaster recovery. Human beings are good at a lot of things, but they aren’t very good at performing detailed repetitive tasks - particularly when there are a lot of other IT issues with which to deal during each day.
These issues, along with basic mechanical problems with the underlying architecture of tape, caused a tremendous number of restore problems and led to the poor reputation that tape enjoys today.
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This led to the creation of the D2D (Disk-to-Disk) solution. Some of the major problems with early D2D solutions were as follow: • The price of disk drives on a per gigabyte level were much higher than the price of tape drives. Even though it was frequently argued by the vendors that this up-front cost had a positive impact on TCO (Total Cost of Operations) and ROI (Return on Investment) due to lower operational expense and fewer recovery errors, the price differential was a significant barrier to adoption. • D2D vendors attempted to replace a relatively simple solution consisting of a tape drive and tapeswith backup software in which the user was forced to purchase, assemble, integrate, monitor, and manage that backup software with backup servers, networking, storage, operating systems, anti-virus, and other components. In short, the lower operational cost promised typically wasn’t realized due to the increased staff-hours required to perform these integration-related tasks.
Present: D2D and Cloud Era
“The problem with the future is that it keeps turning into the present.” [Bill Watterson]
The tape era has now evolved to the D2D and cloud era. Backup tape drive and media revenues decreased by 25% in 2009. [Source: SCCG (Santa Clara Consulting Group)] Looking at backup tape drives alone (without media), there was a 32% decline. For that same period, the most successful format, LTO, showed a decline of 28% in terms of drive revenue.
Some of the major factors that caused the eclipse of the tape era and the rise of the D2D and cloud era were as follow:
• While in 1990 tape had approximately a 50:1 capacity advantage to disk, today that ratio is approximately 0.75:1 with 1.5TB LTO-5 tapes and 2TB SATA drives. The price per gigabyte has been dramatically reduced. At the time this document was being prepared, a common price for a 1.5TB LTO-5 tape was about $50 while a common price for a 1.5TB drive was about $80. • The fundamental technology of tape drives has become more difficult for vendors to advance
as the basic medium becomes increasingly antiquated. The best example of this is LTO-5, which was introduced in 2010. LTO-5 doubled the capacity of the tape but had only a 15% increase in read/write speed. Why? Because it’s increasingly difficult to keep these devices from shoe-shining at higher bandwidth rates.
• Adoption of technology such as RAID-6 has allowed commodity large capacity SATA drives to offer much higher reliability in D2D than can be had with tape.
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• On-premise LAN technology has increased in performance at a faster rate than other interconnect technologies. In addition, the ability to gain overall performance via the multiplexing of backup streams, while possible with multiple tape drives, is simpler and more reliable using on-premise LAN technology.• Deduplication is a technology that allows the price per gigabyte of storage to be reduced. Deduplication requires some form of intermediate disk storage even if tape is used as the ultimate storage medium. The reason for this is that deduplication requires random access in a manner that isn’t compatible with the sequential access methods of tape.
• Cloud-based backup and disaster recovery without an on-premise backup solution offers the ultimate in simplicity for organizations with relatively little data to protect. However, with WAN technology and pricing being fairly stagnant when compared to other technologies such as disk drives, the problem is that even an expensive and fully-provisioned T1 line (telephony-grade symmetric 1.5Mbps WAN) takes from 30-60 days to upload or download a single terabyte of data.
• Cloud-based backup and disaster recovery with an on-premise backup solution offers both local backup and recovery and cloud-based disaster recovery. The major problem with these types of solutions is that the monetization strategy of vendors offering these products and services involves a constant stream of payments from the customer to the vendor for data access to the cloud. In the last few years this has become less expensive; but for companies with terabytes of data to protect it continues to be a barrier to disaster recovery implemented using a metered public cloud.
• Integrated all-in-one backup appliances is making inroads against the traditional software-only model due to an increasing focus on optimizing operational expenditure.
One question that sometimes occurs is whether SAN (and less frequently, NAS) snapshots constitute a fundamental change in the backup paradigm. While snapshots are incredibly valuable, they aren’t a substitute for providing backups of data. Instead, if properly utilized, snapshots can be used to provide better RPOs (Recovery Point Objectives) and RTOs (Recovery Time Objectives) for logical failures while D2D can provide both physical failure protection as well as deeper and more affordable retention. Perhaps more importantly, D2D offers a way to free expensive SAN capacity that is dedicated to snapshots.
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constitutes a fundamental change in terms of the role of backup. Technologies such as VMware’s VADP (vStorage APIs for Data Protection) certainly point to the future of host-level backup for other hypervisor technologies such as Microsoft’s Hyper-V and Citrix’s XenServer; however, even the most advanced virtualization protection relies on the fundamentals of some form of external backup in order to provide data protection.Future: D2D2x Appliance Era
“The future is here. It’s just not widely distributed yet.” [William Gibson]
Based on pricing and technology trends, there are several predictions that today appear to have a high probability of occurring in the next few years:
• Tape will continue its long downward march into irrelevance. The economics and the technology in combination are just too much even if the vendors promoting LTO were able to achieve their roadmap for LTO-6 and beyond. (Note: LTO-5 was not achieved on time and there’s no indication that LTO-6 or future versions of LTO will fare better.)
• SSD (Solid State Disk) drives will become increasingly viable in terms of commonly used primary storage - the pricing per terabyte will rapidly decrease. At the same time, there will continue to be a large gap with respect to the price per terabyte between SSD and large commodity drives - just as there is at present a large gap between the price per terabyte between 15K RPM drives and large commodity drives. Backup data will exist primarily on large commodity drives. • Deduplication will be difficult to achieve on primary storage, but inroads will be made by major
storage vendors that are fueled by the accelerating gap between processor/memory price/ performance versus disk price/performance.
• Virtualization “sprawl and stall” will prove a difficult problem to overcome. 100% virtualized environments will continue to be rare, and operating system, application, and hypervisor heterogeneity will continue to be a major factor to consider when selecting backup.
• SAN and NAS vendors will continue to lower their prices but DAS (Direct Attached Storage) will continue to offer a significant advantage in terms of price and price/performance. As a result, the dream of centralized storage vendors to dominate the “share of wallet” that they hold over their customers will remain an elusive dream - thus storage heterogeneity will continue to be a major factor to consider when selecting backup.
• Cloud-based backup vendors will increasingly take advantage of some form of on-premise appliance as the gap between on-premise performance and off-premise performance grows
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• Cloud-based vendors offering only metered public multiple tenant cloud-based disaster recovery services will find that their growth is limited by private single tenant cloud-based disaster recovery.
• An increasing focus with respect to combining the idea of agile information technology that is adaptable and flexible with leaner staffing models focusing on a reduction in operational expenditure will result in a greater focus on all-in-one backup appliances.
We believe that the future is based on a concept that is termed D2D2x, which stands for Disk-to-Disk-to-Any. D2D2x takes older models such as D2D2T (Disk-to-Disk-to-Tape) and combines it with rotational archiving via D2D2D (Disk-to-Disk-to-Disk), private single tenant cloud-based disaster recovery, and public multiple tenant cloud-based disaster recovery (D2D2C - Disk-to-Disk-to-Cloud.)
About Unitrends
Unitrends offers a family of affordable integrated all-in-one on-premise backup appliances that support disaster recovery via disk-based archiving as well as electronic vaulting to private- and public-clouds. Unitrends is customer-obsessed, not technology-obsessed, and is focused on enabling its customers to focus on their business rather than on backup. For more information, please see our web site at http://www.unitrends.com/.
