LTO-8 is a tape format from the Linear Tape-Open Consortium released in late 2017. It succeeded the LTO-7 version, which launched in 2015.
An LTO-8 cartridge offers 30 terabytes (TB) of compressed storage capacity and 12 TB of uncompressed capacity. Sustained data transfer rates are 750 megabytes per second (MBps) for compressed data and 360 MBps for uncompressed data. LTO-8 -- as with LTO-5, LTO-6 and LTO-7 formats -- offers partitioning, encryption and the write once, read many (WORM) feature. LTO-8 tape drives are backward-compatible to one generation, so they can read and write to LTO-7 tapes.
LTO is an open tape format developed and updated by Hewlett Packard Enterprise (HPE), IBM and Quantum -- the members of the LTO Consortium.
LTO-8 uses tunnel magnetoresistance (TMR) for tape heads, a switch from the previous giant magnetoresistance (GMR). TMR provides a more defined electrical signal than GMR, allowing bits to be written to smaller areas of LTO media. The LTO-8 tape head with TMR enables higher density, lower susceptibility to media discrepancies, cooler temperatures and better signal sensitivity, according to vendor Spectra Logic. GMR heads had reached their density limit.
LTO-8 also uses barium ferrite instead of metal particles for capacity improvement. Barium ferrite -- a type of magnetic particle -- can be reduced in size to improve recording density without magnetic signal loss.
New versions of LTO have traditionally been able to read back two generations and write back to one generation. For example, LTO-7 drives could read LTO-5 and LTO-6 cartridges and write to LTO-6. With LTO-8, the inclusion of TMR technology and barium ferrite limits backward compatibility to one generation. As a result, LTO-8 can read and write to LTO-7.
As with previous generations, LTO-8 features the WORM capability, the Linear Tape File System (LTFS) and encryption. By allowing users to write to the tape only once, WORM ensures data is not overwritten and helps with compliance. Through LTFS, the tapes offer partitioning, which tells the LTO tape drive exactly where a file is stored and improves file control and space management. And the 256-bit Advanced Encryption Standard (AES) enhances security and privacy when tapes are stored and shipped.
Tape is a strong choice when securing data storage against ransomware and other cyberattacks. It offers offline data protection, keeping data isolated from networks susceptible to viruses.
LTO-8 also has a reliability of a 10-19 bit error rate.
LTO-8 tape capacity
Two of the biggest benefits of tape storage are capacity and its distinct product roadmap. With the roadmap, LTO essentially doubles tape storage capacity with each new generation. With even small businesses handling data in the hundreds of terabytes or even petabyte (PB) levels, capacity is a key element of storage.
The 12 TB of uncompressed capacity featured in LTO-8 is equivalent to 8,000 movies, 2,880,000 songs or 7,140,000 photos, according to Spectra Logic. In the last 10 years, LTO has increased capacity by 1,400%.
The LTO Program introduced a new feature with LTO-8: The drive can write 9 TB uncompressed on a new LTO-7 cartridge, instead of the typical 6 TB. That medium is labeled an "LTO-7 initialized LTO-8 Type M cartridge," according to the LTO Program. Only new LTO-7 cartridges can be initialized as LTO-8 Type M. The initialized cartridge can only be read and written in an LTO-8 drive. It offers 22.5 TB of compressed capacity.
LTO-8 vs. LTO-7
LTO-8 doubled the capacity of LTO-7, from 6 TB to 12 TB uncompressed and 15 TB to 30 TB compressed. The capacity compression ratio of 2.5-1 is the same. It also has the same number of channels at 32.
LTO-8 features a performance increase from 300 MBps to 360 MBps for the uncompressed data transfer rate and from 700 MBps to 750 MBps compressed.
According to analyst Jon Toigo, "LTO-7 may be the last iteration catering to small to medium-sized customers, given its price point of about $100 per 6 TB cartridge (15 TB compressed)."
LTO-7 drives can read LTO-6 and LTO-5 cartridges and write back to LTO-6, while LTO-8 can only read and write back to LTO-7.
LTO tape roadmap and future directions
LTO-1 was the first version of the LTO technology to serve as an open standard substitute to the available formats of the day. It has native capacity of 100 gigabytes (GB) and a native transfer speed of 20 MBps.
LTO-2 offered 200 GB capacity (400 GB compressed) and 40 MBps throughput (80 MBps compressed), doubling the speed and capacity of LTO-1. Capacity and data transfer rates for LTO-2 assume a 2-1 compression ratio.
LTO-3 doubled native capacity to 400 GB (800 GB compressed) and transfer rates to 80 MBps (160 MBps compressed). It was the first LTO format to feature WORM.
LTO-4 again doubled capacity to 800 GB native capacity (1.6 TB compressed) and boosted transfer rates to 120 MBps (240 MBps compressed). LTO-4 also included 256-bit AES-Galois Counter Mode drive-level encryption.
LTO-6 features 2.5 TB native capacity (6.25 TB compressed), with native sustained data transfer rates as high as 160 MBps (400 MBps compressed).
The consortium has formats in its roadmap up to generation 12 of LTO Ultrium tape technology. The projected specifications for each format are as follows:
- LTO-9: 24 TB capacity (60 TB compressed)
- LTO-10: 48 TB capacity (120 TB compressed)
- LTO-11: 96 TB capacity (240 TB compressed)
- LTO-12: 192 TB capacity (480 TB compressed)
The 480 TB compressed capacity of LTO-12 will be 16 times higher than the 30 TB compressed capacity of LTO-8.
All future generations -- which typically come out every two to three years -- are projected to feature WORM, partitioning and encryption.
In the past, users would often skip an LTO generation when upgrading, as the increase in capacity was not high enough to encourage a change to the higher LTO format. For example, moving from LTO-5 to LTO-6 increased the uncompressed capacity by only 1 TB. Now, each new LTO release has a large enough capacity increase to warrant an immediate upgrade.
In addition, starting with LTO-8, tape drives will be able to only read back one generation -- versus the previous two -- which will encourage organizations to upgrade faster.
In August 2017, IBM and Sony said they had developed technology for the highest recording areal density for tape storage media. The result can support storage of approximately 330 TB uncompressed per cartridge.
What tape is used for
Tape has lost favor to disk as a primary and backup data storage medium, but it is still a popular choice for long-term storage and archiving because of its high capacity, low cost, sturdiness and portability. The massive storage capacity -- especially of LTO-8 -- can help with long-term retention of huge data sets that continue to grow.
Tape stored off site is also an option for disaster recovery, in the event a primary data center goes down because of a natural disaster or human error. Disk offers a better option for organizations that need quick data recovery and random access. Disk-based storage is generally more expensive than tape, but tape-based storage does not provide random access.
Tape is often used by industries such as media, entertainment and the sciences, which can create large volumes of data daily and need a storage medium that's less expensive than disk.
A tape library is a collection of cartridges and drives. A typical library contains multiple drives for reading and writing data, access ports for entering and removing tapes, bar codes for tracking, and a device for mounting and dismounting cartridges. A library can include hundreds or thousands of tapes.
A tape library must be compatible with the rest of an organization's data protection platform, including its backup software. Organizations of all sizes use tape libraries. An enterprise will often use a tape library as a secondary backup or an archive, if not as a primary backup.
Tape libraries are capable of containing massive amounts of capacity. When fully populated with LTO-8 drives and LTO tape media, Spectra's libraries will support at least 1 petabyte (PB) of compressed storage capacity. The Quantum LTO 3U scalable library can house 300 TB uncompressed -- and at least 600 TB compressed -- of LTO-8 tape storage for backup, archive and other secondary uses, according to analyst Toigo. Other tape library vendors include IBM, Dell EMC and HPE.