I have noticed a pattern of Google searches related to the question “Can LTFS be used with LTO4 media?”. This question is implicitly answered in other posts but the frequency of the Google searches motivate me to post the following explicit answer.
LTFS relies on the cartridge partitioning support that was introduced in the LTO5 specification by the LTO Consortium. Earlier generations of LTO media and drives do not have this partitioning capability and are therefore unable to support the LTFS on-tape format.
Support for multiple partitions at the media and hardware level is the key enabling functionality that allowed my team at IBM to invent and implement the LTFS technology. The details of how LTFS uses partitioning and the tape media are the subject of other posts on this blog, specifically Partitioning in LTO5 and LTFS, and How does LTFS work?.
Without partitioning support there are limited options for where the file-system metadata (or “Index”) may be stored on the media. With LTO generations prior to LTO5 these limited options are all that we have to work with. None of these options provide a satisfactory mix of performance, data safety, and business opportunity to make it practical to pursue LTFS on these older generations.
LTFS is available for LTO5 from all current drive vendors (IBM, HP, and Quantum). Additionally, LTFS is available for IBM’s enterprise tape product the TS1140 (aka Jaguar) and has been ported by Oracle to their T10000C product line. At this point LTFS has been adopted by all actively developed data tape technologies.