The latest generation of Linear Tape Open, LTO-9 was shipped in 2021, but the release was clearly hampered by the pandemic. Despite Symply leading the LTO-9 charge and being the first to market with desktop and rack mountable LTO-9 Full Height and Half Height drives respectively, it has taken the market some time to adopt LTO-9.
For LTO-9 the ride has not been smooth, the development cycle was four years, as opposed to the usual three years, and the capacity was only 18TB native instead of 24TB native, as originally road mapped. Typically, LTO capacity doubles every generation, see below.
The latest published road map shows that the doubling of capacity is going to return with LTO-10, providing 36TB native per tap. LTO-10 is rumoured to be on course for release towards the end of 2024.
Let’s start at the beginning. What is LTO-9? We have seen LTO-9 Full Height and Half Height tape drives provide even higher capacity and performance (with Full Height drives) than previous generations, and Symply was the first company to offer the drive technology in a variety of form factors including Thunderbolt3 and SAS connectivity, in desktop and rack-mounted configurations. LTO-9 offers a native capacity of up to 18TB and up to 45TB compressed (assuming 2.5:1 compression). LTO-9 is fully compatible with Linear Tape File System (LTFS), and the LTO-9 drive mechanisms can read and write to the previous generation LTO-8 cartridges. Like LTO-8 the technology is only backwards compatible one LTO generation.
LTO-9 Full Height vs Half Height drives. LTO-9 drives are available in both Full Height and Half Height formats and are available from Symply. Let’s see how they stack up.
You can see the primary difference between LTO-9 Full Height and Half Height drives is the performance, with the Full Height drive providing an extra 100MB/Sec of throughput. The additional speed also means faster seek times to data on the tape so that read or write operations begin faster on Full Height drives compared to their Half Height counterparts. It is also worth noting that the higher performance of the Full Height drives is also seen when reading and writing to LTO-8 cartridges.
Full-Height drives also have much higher reliability for load and unload cycles, that is not to say in any way that Half Height drives do not have high reliability for loading and unloading media, just that as Full height drives were originally designed for enterprise tape libraries, thus are built to a higher specification.
Changes to LTO backwards compatibility that started with LTO-8. In the past LTO technologies have always been able to read back two generations, and write back one generation. So, an LTO-7 drive could read LTO-7, 6 and 5 tapes, and could also write LTO-7 and LTO-6 tapes. This read backwards two generations ended with LTO-8, meaning that an LTO-8 drive will read and write LTO-8 and LTO-7 tapes, but cannot read LTO-6 tape. Likewise, an LTO-9 drive will read and write LTO-9 and LTO-8 tapes, but will not read LTO-7.
This change to backwards compatibility was driven by the never-ending demand for capacity, speed and reliability of new generations of LTO, primarily driven by the large public cloud hyperscalers that are desperately in need of ever higher capacity tapes and hard disks to sustain the ever-increasing data they are storing. This demand for capacity meant that there had to be a change in the underlying head technology and media composition. Earlier versions of LTO used Giant Magnetoresistive (GMR) read/write heads that had reached their density limits. LTO-8 and LTO-9 drives now use Tunneling Magnetoresistive (TMR) read/write heads, a technology that unlocked more density, performance and reliability for LTO.
LTO-9 also utilizes Barium Ferrite (BaFe) media, similar to LTO-7 and LTO-8 (vs. metal particle, or MP used in LTO-7 and older generations), in order to continue the significant gains. The combination of the new TMR heads and BaFe media has increased capacity and performance, but limited the backward compatibility to a single generation. This change will obviously affect how current users of LTO technology approach upgrading to LTO-9 drives. We will consider these possible workflows for upgrading to new drive technology as well as some thoughts around the migration of older media to newer tape formats, after a quick recap on backup and archiving.
Backup and Archiving – are not the same thing. Before we talk about migration strategies and how to approach new technologies, it is worth having a recap over the difference between, Backup and Archive:
Backup creates a copy of data and restores it in case of data loss or corruption. A company may have multiple copies of the same information for backup purposes. Increasingly, flash or disk drives are the primary targets for first line backup, but many organizations still use tape for secondary, immutable (WORM), and air-gapped backup targets.
Backup LTO tapes are very rarely migrated between LTO generations, as typically backup data sets are very short-lived and can be defined in weeks or at most months. So there is little or no point in migrating backup tape sets between LTO generations.
Archiving creates a ‘master’ copy of a file, typically on a less expensive storage platform. The archive copy is used to free up the obligation to continue to backup that data and permit the more efficient use of primary storage systems, or backup storage.
Archiving can use tiered storage and intelligent software to protect data and provide fast and efficient access. As the amount of data retained in archives expand, an active archiving system combines highly scalable archive storage, like LTO technology, with intelligent software that uses rich metadata, indexes, directories, and tags to unlock archives. Tapes used in archiving, especially active archives, are more likely to be prioritized for migration between LTO generations.
Tapes that are used in more compliance-type archiving, have policies typically dictated by governments or industry bodies. These tend to have defined expiry dates, and longer retrieval time frames than other archives, so it is less frequently accessed, if at all.
Whether you are backing up or archiving, or a mixture of both, may change the strategies that you deploy.
Considerations for upgrading LTO. Upgrades between LTO generations are typically driven by the requirements to increase capacity and/or performance. Traditionally as LTO supported the read backwards two generations, it was common practice for LTO users to skip a generation between upgrades of technology. In many instances, this made practical and economic sense for LTO customers.
For example, the difference between performance and capacity increase from LTO-5 to LTO-6 was minimal with native capacities going from 1.5TB to 2.5TB, so many LTO users did not see a compelling reason to upgrade from LTO-5 to LTO-6. However, the increase from LTO-6 to LTO-7 was much greater in terms of both capacity and performance than that of LTO-5 to LTO-6. LTO-7 offered a native capacity of 6TB and performance of 300MB/Sec so it was a big step up from not only LTO-6 but also a substantial difference from the LTO-5 capacity of 1.5TB. This meant for the vast majority of LTO users there was a clear-cut case for migrating from LTO-5 to LTO-7. So it is easy to see that until LTO-8 this skipping of a single generation of LTO was a valid strategy for managing backups and archives.
Things are different if a customer skipped two generations of LTO for example migrating LTO-4 to LTO-7, the customer would have to consider what to do as the LTO-4 media could not be read in an LTO-7 drive. From LTO-8 onwards, the decision to skip just a single generation will need to be considered carefully.
As mentioned earlier in this document, technological advancements have resulted in significantly larger increases in capacities between newer LTO generations. For instance, between LTO-7 and LTO-8, and LTO-8 and LTO-9, there has been a capacity increase of 6TB, which is much higher compared to previous generations.
According to the guidance provided by the LTO consortium, although LTO-9 did not achieve the doubling target from LTO-8 (due to pandemic-related development setbacks), the doubling of capacity is expected to resume from LTO-10 onwards, as indicated in the roadmap. This will make upgrading with each LTO release more compelling due to the increased capacity, and the ability to read/write back a single generation, making data access and migration easier.
Migration Factors to Consider. Whether you operate at data centre scale or smaller, customers may have a significant number of tapes relative to the size of their operations, and face the same decisions when it comes to migrating LTO media. While the desire may be to migrate all old media to new media, this may not be necessary or practical. It’s important for customers to understand which media needs to be migrated and which does not. For example, it’s entirely possible that content on aging media is no longer required, and the media can be retired. Conversely, some media is highly likely to be accessed again and will need to be migrated.
Types of Migration – Traditional. Traditional migration refers to the process of restoring data from existing archives and backups to a primary storage and then migrating the media from the primary storage to the new LTO generation.
For example, an LTO-7 tape drive with the correct backup/archive software solution could be used to restore data from LTO-5, 6, and 7 tapes to a primary disk storage system, and then the same or even alternative software could be used to backup/archive the data to the latest LTO-9 generation tape drive and tapes.
Since this requires a full restore and rewrite, it is best performed as a task in the background over a period of time. When all the data tapes are migrated the older generation LTO drive and media can be retired.
Types of Migration – Tape to Tape Copy . “Tape to Tape Copy Migration” refers to a migration process that does not involve data being restored to a primary disk or flash storage device in order to be backed up or archived to a new generation of LTO tape. This is made possible by certain backup/archive software applications. In archive environments, it has been made easier by the fact that since LTFS (Linear Tape File System) became a standard format implemented initially in LTO-5, the vast majority of data archived on LTO is in the open LTFS format. This means that it can be read and written by a wide range of software applications that offer a significant return on investment.
In a Tape to Tape Copy Migration, the fact that the data does not need to be restored to a primary storage tier means that migrations can happen much quicker and without the need for using space on a more expensive primary storage volume.
In practice, a combination of both traditional and tape-to-tape copy migration policies is likely to be deployed, along with the policy of retiring material that is no longer needed. The ultimate goal of moving older LTO media to LTO-9 media. This will ultimately increase capacity, save time and even reduce the hardware footprint required to carry our backup/archive tasks.
Do I need to migrate? Some usage models mean that some customers have decided not to migrate, like the larger corporates, hyperscalers, and institutions involved in high-performance computing. The data sets may be too large to migrate and the user just maintains older generation LTO drives to read older LTO media, if required. But data capacities do not have to be excessively large to skip migrating media, many small and medium-sized customers are also doing this, just leveraging newer drive generation and gaining the benefits of the higher capacities, while they maintain older LTO drives as required. There is certainly no shortage of companies that offer the ability to read older generations of LTO media as required.
How Can Symply Help? From desktop SAS and Thunderbolt-enabled tools to full rack-mounted systems, Symply’s line-up of LTO products offers a unique take on the world of long term storage: we built them to answer the actual challenges faced by businesses and end users. Our solutions include both Half-Height and Full-Height LTO drives from LTO-7 to LTO-9, as well as special availability on LTO-6 for those customers that need to read LTO-4. Our dual-drive desktop and rack solutions can be configured to support both LTO-7 and LTO-9 in the same enclosure allowing easy support for both Traditional and Tape to Tape Copy Migration processes. Symply hardware is compatible with industry-leading LTO backup/archive software applications including but not limited to Archiware P5, Hedge Canister, StorageDNA, Tiger Technology Bridge, XenData, and YoYotta.
