What you'll learn in this tip: Despite decreasing sales revenue in 2009, tape remains a popular storage media,...
but why is that? This tip explores some of the reasons why backup to tape is still popular, and takes a look at the latest iteration of LTO tape technology, LTO-5.
As much as we hear about tape storage media being a technology of the past, we keep seeing evidence that it's still a widely used, evolving technology. According to the Back-up Tape Technology: 2010 report published by the California-based Santa Clara Consulting Group, tape drive and media sales revenue were off by approximately 25% in 2009.
While these figures aren't promising at the onset, a few factors must be taken into consideration before assuming this is proof of the end of an era in the world of storage. We must consider that a decrease in revenue can be driven by lower prices due to a more competitive market, and does not necessarily represent an equivalent decrease in the number of units sold. More than 32 million tape cartridges were sold in 2009 alone, which is not exactly an indicator of a dead technology, especially considering these cartridges will remain in circulation for a number of years. We must also look at the entire storage revenue -- including disk -- which also may have been affected in 2009 due to the economic slowdown and more competitive market conditions.
The fact that major manufacturers like Hewlett-Packard (HP) Co., IBM Corp. and Quantum Corp. are still working on the development and roadmap of Linear Tape-Open (LTO) technology as demonstrated by the latest release (LTO-5) is a also a good indication that the future of tape storage is not as grim as many disk vendors like to claim.
But why backup to tape?
With the random-access nature of disk storage, the ability to leverage local and remote replication, or mirroring for near-instant recovery, why would anyone ever want to backup to tape? In addition, the space occupied by data on disk can be reduced through data deduplication, making disk an even more appealing media.
The reason for the continued use of tape is still relatively simple. Data will age, its value to the business will slowly decline and eventually, the lowest possible cost of storage is desirable. Many data protection environments are now tiered and leverage replication technologies (snapshot, mirror, remote copies, etc.) for critical data with tight recovery time objectives (RTOs) and recovery point objectives (RPO). This typically only applies to specific data sets and copies are normally only kept for a limited number of days for cost reasons. The second tier consists of disk arrays with lower performance, high-capacity drives for less critical or aging data sets; this is typically where deduplication is implemented and data copies can be kept for months.
In addition, businesses are now facing numerous regulatory compliance issues that can be difficult to understand. As a result, companies chose to archive data for periods as long as five, seven and even 10 years. And depending on the frequency and the type of data, the volume of archived data can exceed the amount of production data (current data used daily) by a factor of 10 times, 20 times and even more. Storing all this archive data on disk can be costly and this is where tape media still shines.
Data archiving and tape storage
Here are a few more reasons why tape is still a very good choice for data archiving and long-term storage:
- A tape that isn't mounted in a drive consumes no energy. Yes, there are now disk drives that can be powered down when not in use, but because data will likely not be accessed at all unless there is a legal request, why put it on disk at all?
- You can store tapes at a lower cost location rather than using your top-dollar data center space for archive disk arrays.
- Backup software such as CommVault Simpana now offer data deduplication to tape, making it no longer exclusive to disk storage.
- With the release of LTO-5, tape drives can now store 1.5 TB of data in native mode and up as much as 3 TB, assuming 2:1 compression is achieved. Assisted with deduplication at the software level, a LTO-5 tape could hold even more depending on the nature of the data.
There is also a business reality we must all face and that we often tend to ignore; unless your business depends on dozens or hundreds of critical servers with large volumes of data, that must be restored in fewer than 24 hours (RTO) and little tolerance for data loss (RPO), tape is still a very viable backup media option. Many enterprises and even SMBs are very satisfied with being able to restore a small number of critical servers within 24 hours.
A look at LTO-5 tape storage
Let's look at some of the features of LTO-5 tape, the latest iteration of LTO technology, which still makes tape restore a viable option for many companies.
As mentioned earlier, LTO-5 can hold 1.5 TB of data native (3 TB with 2:1 compression) and achieve throughputs of 140 MBps (280 MBps with 2:1 compression). In addition, LTO 5 is WORM-capable like LTO-3, and also offers data encryption like its predecessor, LTO-4 tape. The latest feature available with LTO-5 is the media partitioning. This new technology allows the creation of two partitions on the media. This allows the tape to be self-describing with one partition holding content and the other indexing information.
LTO-5 drives are read-and-write backward-compatible with LTO-4 tape and read-compatible with LTO-3 media, which supports investment protection by helping alleviate the higher cost of the latest media (currently at around $120 for LTO-5 vs. approximately $40 for LTO-4) until the price for LTO 5 starts dropping.
Over the years, many businesses -- including most SMBs -- have invested in the purchase of a tape storage infrastructure to support the majority of their backup and archive needs and as explained earlier, tape technology still offers acceptable performance in many cases due to smaller amounts of data and fewer critical servers to recover within a given window. Most of those SMBs will need a compelling business and financial argument to replace a technology in which they have made an investment, and which in most cases still meets their backup and archive requirements. This also means we can expect to see tape libraries in the server room for a few more years.
About this author: Pierre Dorion is the data center practice director and a senior consultant with Long View Systems Inc. in Phoenix, Ariz., specializing in the areas of business continuity and DR planning services and corporate data protection.