LTO Ultrium generations explained
Capacities from LTO-7 to LTO-10, the roadmap to LTO-14 (913 TB), and the all-important read/write compatibility matrix — so you buy the right generation and can still read what you’ve already got.
Native capacity per generation
LTO-9 ships today at 18 TB native; LTO-10 reaches 40 TB; the roadmap runs to LTO-14 at up to 913 TB.
Compressed figures assume a 2.5:1 ratio and vary by data type. The roadmap continues LTO-11 → LTO-14 (up to 913 TB native).
Read/write compatibility
The key planning question when you upgrade: which media can the new drive use? From LTO-8 the rule tightened to one generation back; LTO-10 starts fresh with no backward compatibility.
LTO generations — FAQs
What is the capacity of each LTO generation?
Native (uncompressed) per cartridge: LTO-7 6 TB, LTO-8 12 TB, LTO-9 18 TB, LTO-10 40 TB. Compressed capacity (at 2.5:1) is roughly LTO-7 15 TB, LTO-8 30 TB, LTO-9 45 TB, LTO-10 100 TB. The published roadmap continues through LTO-11, 12 and 13 to LTO-14 at up to 913 TB per cartridge.
Is LTO backward compatible?
Up to LTO-7, drives could read two generations back and write one back. From LTO-8 onward (a new media format), drives read and write just one generation back — so an LTO-9 drive uses LTO-9 and LTO-8 media. LTO-10 introduces another new format and is not backward compatible at all (LTO-10 drives use LTO-10 media only). Plan media migration accordingly when you jump generations.
Can an LTO-9 drive read my old LTO-7 tapes?
No — an LTO-9 drive reads and writes LTO-9 and LTO-8 only, not LTO-7. If you need to read LTO-7 media you must keep an LTO-7 or LTO-8 drive, or migrate the data forward before retiring those drives. We help plan these migrations.
What is LTO Type M (M8)?
Type M (M8) let an LTO-8 drive initialise a brand-new LTO-7 cartridge to 9 TB native (instead of 6 TB) as a cost-saving bridge. It applies only to never-before-written LTO-7 media in an LTO-8 drive. It’s a niche option; most buyers simply use the native media for their drive generation.
What does WORM mean for LTO?
WORM (Write Once, Read Many) cartridges can be written once and never altered or erased — the data becomes immutable. WORM media is available across LTO generations and is widely used for compliance and legal-hold archives where tamper-evidence matters. WORM cartridges are visually two-tone so they’re easy to identify.
Is LTO tape encrypted?
Yes — hardware AES-256 encryption is built into LTO drives from LTO-4 onward, so data is encrypted at write speed with no performance penalty. Keys are managed by your backup software or an external key manager. This is especially important for cartridges shipped or stored off-site.
How long does LTO media last?
LTO cartridges are rated for an archival life of 30+ years under proper storage conditions, and for thousands of load/unload and full read/write passes. That longevity, combined with offline air-gap and WORM, is why tape remains the standard for long-term and compliance archives.
Which generation should I buy today?
For new deployments, LTO-9 (18 TB native) is the mainstream, widely-supported choice with broad library availability; LTO-10 (40 TB) suits the largest archives where its higher capacity offsets the lack of backward compatibility. We’ll match the generation to your data volume, retention and existing media estate.
Plan your LTO generation & library
We’ll match the LTO generation, drives, media and library to your data volume, retention and existing media — and plan any migration.