Spectra Logic E-Books
|Tape Drive Technology Comparison||Enterprise Tape: Performance|
|Date: October 2014
Table of Contents
|Date: July 2014
Table of Contents
LTO technology is a commonly used drive technology for tape libraries, but other drive technologies are worth evaluating, as well. Two additional technologies, TS11x0 and T10000D, are evaluated and compared to LTO technology. These two drive technologies provide significant benefits.
Tape technology’s speed, affordability, and reliability make it increasingly central to data protection as the volume of data continues along its steep growth trajectory. This growth has propelled tremendous advances in physical tape digital storage technologies over the past ten years. These advances warrant further analysis that can help data storage customers select the right tape technology for each data protection environment.
Tape dominates as the storage industry’s preferred form of removable media, and remains the hands-down leader in additional categories that include cost and reliability. The archival lifetime of tape for storing data securely, and maintaining the data’s integrity, is unmatched, with an archival life of 30 or more years given an easily maintained environment. Further, the IBM and Fujifilm announcement in 2014 of a 154 TB (native) capacity tape and the Sony announcement in 2014 of a 185 TB (native) capacity tape demonstrate tape has a long, viable future.
This white paper examines the major tape technologies that compete in the medium–sized and enterprise organizations market. The competitors include LTO, offered by IBM and HP, and proprietary drives from Oracle, and IBM. The proprietary drives advantages are performance, capacity, reliability, and roadmap.
The drives reviewed are typically used in automated tape libraries, and are evaluated in that context. Some libraries provide automation features that play a significant role in maintaining data integrity through drive and tape health management, a consideration that may affect tape choices given the enhanced data reliability through automation. Further, some drives have innovative features that warrant mention in this analysis.
This paper examines the following tape technologies:
- Linear Tape Open/LTO-6
- TS11x0 Technology/TS1150
This paper covers the following information regarding each tape drive technology:
- Drive technology introduction
- Recording methodology and mechanics
- Performance/transfer rates and capacity
- Data streaming to optimize performance
- Power Use
- Read/write compatibility with earlier generations of tape
- Enterprise-class reliability of media and drives
- Load/Rewind and access times
- Recent technology enhancements
- Technology roadmap
Selecting tape technology is typically driven by capacity, performance, reliability, cost and a documented roadmap. However, this information may be obscured on specification sheets, each emphasizing certain aspects of technology, or using non-standard nomenclature in describing a wide range of features. Distinguishing the useful from the less useful requires some understanding of the technology and how tape has been used.
Unless otherwise noted throughout this paper, the following conventions have been used:
- The values in this paper reflect those specified for each technology’s most recent generation/largest media—the largest tape cartridge, for example.
- When multiple values have been identified for any specification, the value from the most trusted source is used. For example, real world testing by a trusted source is used in place of vendor-supplied numbers, unless the delta between the values is large, in which case all values are shown and the discrepancy is discussed.
Data used is typically for Fibre Channel drives operating at maximum typical use.
- All values are native (that is, no compression is assumed).
- Values may have been rounded.
Data access times are a crucial consideration for tape library purchases in processing-intensive environments. Using the right metrics and understanding them in the context of how the library will be deployed is important in selecting the right system. Multiple variables and use cases should be considered in order to acquire the right library for use today and well into the future.
IT professionals managing enterprise storage environments face many challenges, including processing staggering amounts of data that grow larger every year, and completing backups and archiving in short periods of time. Finding a tape library that meets processing speed requirements is therefore very important; however, doing so is not as straightforward as looking at a simple performance metric. Furthermore, each data center processes data differently according to internal processes and requirements, so the best library for one organization might not be the best for another.
The best way to determine the true speed of a system and the best tape library to choose is to fully research and evaluate several characteristics of the drives and library robotics, and consider how they interact with data processing requirements. Failing to do risks choosing a solution that is poorly suited to the storage tasks it needs to perform.
Overview of Attributes Affecting Performance
Enterprise Tape performance is important in order to reduce non-productive backup window times and improve data response times. For tape automation systems, two major components affect performance:
- Tape Drive:
- Speed at which tape drives access data, or Average Time to Access
- Rate at which they subsequently read or write data, or Tape Drive Throughput
- Library Robotics:
- Speed of the tape robots in retrieving tape cartridges and providing them to the tape drives.
Additionally, the above items are of varying importance and impact depending on the data and processing requirements in each IT environment.
Tape drive and library vendors provide a number of features and innovations designed to improve performance within both of these arenas. The following sections cover the essentials of the attributes, then provide specifics on how Spectra libraries with TS1140/TS1150 technology tape drives and other innovations provide value for these attributes.
- Tape drives
- Library robotics
- Library use case for drives and robotics
When considering the overall workload of an automated tape system, tape drive reads and writes normally constitute the bulk of work since they may run continuously while tape robots operate intermittently. For example, a library robot may spend seconds locating and moving a tape to a drive while that same tape drive may spend hours writing data to the tape. Since tape drives do the majority of the work within the automated system, tape drive performance is the first area tape users should understand.
There are two important drive attributes: average time to access, and tape drive throughput.
Average Time to Access
Multiple operations or factors are included in assessing the average time to data access of a tape drive. These factors can include:
- The time needed to load a tape into a drive and thread the tape media through the drive tape path so it crosses the tape read / write heads.
- Time to locate the appropriate data block on the tape.
- Speed at which the tape is traveling as it moves to the data block.
- The total length of the tape. The longer the tape, the longer it takes to reach the last data block.
The average time to access data is a critical service-level metric for a drive. Consequently, users should consider not only the individual performance factors in the previous list, but should look at them as a sum of the parts when comparing enterprise and midrange tape drive performance as part of the total solution.