SNIA announced LTFS Format Specification 2.5 is now under public review in Mar 2019. You can check the new version here. And also you can make any feedback from the SNIA site (http://snia.org/tech_activities/publicreview/#ltfs).

Linear Tape File System (LTFS) is a filesystem to mount a LTFS formatted tape in a tape drive. Once LTFS mounts a LTFS formatted tape as filesystem, user can access to the tape via filesystem API.

Objective of this project is being the reference implementation of the LTFS format Specifications in SNIA.

At this time, the target of this project to meet is the LTFS format specifications 2.4. (https://www.snia.org/sites/default/files/technical_work/LTFS/LTFS_Format_2.4.0_TechPosition.pdf).

LTFS Format Specification is specified data placement, shape of index and names of extended attributes for LTFS. This specification is defined in SNIA first and then it is forwarded to ISO as ISO/IEC 20919 from version 2.2.

The table below show status of the LTFS format Specification

These instructions will get you a copy of the project up and running on your local machine for development and testing purposes.

• Linux

  • automake 1.13.4 or later
  • autoconf 2.69 or later
  • libtool 2.4.2 or later
  • fuse 2.6.0 or later
  • uuid 1.36 or later (Linux)
  • libxml-2.0 2.6.16 or later
  • net-snmp 5.3 or later
  • icu4c 4.8 or later

• OSX (macOS)

  Following packages on homebrew

  • automake
  • autoconf
  • libtool
  • osxfuse (brew cask install osxfuse)
  • ossp-uuid
  • libxml2
  • icu4c
  • gnu-sed

• FreeBSD:

  • FreeBSD 10.2 or 11.0 or later (for sa(4) driver changes)
  • automake
  • autoconf
  • libtool
  • fusefs-libs
  • net-snmp
  • e2fsprogs-libuuid
  • libxml2
  • icu

• NetBSD:

  • NetBSD 7.0 or higher (for FUSE support)
  • automake
  • autoconf
  • libtool
  • libfuse
  • net-snmp
  • libuuid
  • libxml2
  • icu

./autogen.sh
./configure
make
make install

./configure --help shows various options for build and install.

LTFS uses the sg driver by default. You can improve performnce and reliability to change parameters of the sg driver below.

allow_dio=1
def_reserved_size=1048576

In RHEL7, you can put following file as /etc/modprobe.d/sg.conf.

options sg allow_dio=1
options sg def_reserved_size=1048576

You can check current configuration of sg driver to see the file /proc/scsi/sg/debug like

$ cat /proc/scsi/sg/debug
max_active_device=44  def_reserved_size=32768
 >>> device=sg25 1:0:10:0   em=0 sg_tablesize=1024 excl=0 open_cnt=1
   FD(1): timeout=60000ms bufflen=524288 (res)sgat=16 low_dma=0
   cmd_q=1 f_packid=0 k_orphan=0 closed=0
     No requests active
 >>> device=sg26 1:0:10:1   em=0 sg_tablesize=1024 excl=0 open_cnt=1
   FD(1): timeout=60000ms bufflen=524288 (res)sgat=16 low_dma=0
   cmd_q=1 f_packid=0 k_orphan=0 closed=0
     No requests active

In the lpfc driver (for Emulex Fibre HBAs), the table size of the scutter-gather is 64 by default. This cofiguration may cause I/O errors intermittenly when allow_dio=1 is set and scutter-gather table cannot be reserved. To avouid this error, you need to change the parameter lpfc_sg_seg_cnt to 256 or larger like below.

options lpfc lpfc_sg_seg_cnt=256 

In some versions of the lpfc driver (for Emulex Fibre HBAs), the table size of the scutter-gather cannot be changed correctly. You can check the value is changed or not in sg_tablesize value in /proc/scsi/sg/debug. If you don't have a correct value (256 or later) in sg_tablesize, removing allow_dio=1 configuration of the sg driver is strongly recommended.

You need to add --enable-lintape as an argument of ./configure script if you want to build the backend for lin_tape. You also need to add DEFAULT_TAPE=lin_tape if you set the lin_tape backend as default backend.

Dist	Arch	Status
RHEL 7	x86_64	OK
RHEL 7	ppc64le	OK
CentOS 7	x86_64	OK
CentOS 7	ppc64le	Probably OK
Fedora 28	x86_64	OK
Ubuntu 16.04 LTS	x86_64
Ubuntu 18.04 LTS	x86_64	OK
Debian 9.5	x86_64	NG
ArchLinux 2018.08.01	x86_64	OK
ArchLinux 2018.12.31 (rolling)	x86_64	OK

Currently, automatic build checking is working on Travis CI with Ubuntu 16.04 LTS.

In Debian9 (stretch), ICU 57.1 is used but the command genrb in this version causes crash while creating a resource bundle of LTFS. It is clearly a bug of ICU package and this problem was fixed into ICU 60 at least. May be we need to wait Debian10 (buster) because ICU 60 is used in Debian10 at this time (in the test phase of Debian10).

Before build on OSX (macOS), some include path adjustment is required.

brew link --force icu4c
brew link --force libxml2

On OSX (macOS), snmp cannot be supported, you need to disable it on configure script. And may be, you need to specify LDFLAGS while running configure script to link some required frameworks, CoreFundation and IOKit.

./autogen.sh
LDFLAGS="-framework CoreFoundation -framework IOKit" ./configure --disable-snmp
make
make install

./configure --help shows various options for build and install.

Note that on FreeBSD, the usual 3rd party man directory is /usr/local/man. Configure defaults to using /usr/local/share/man. So, override it on the command line to avoid having man pages put in the wrong place.

./autogen.sh
./configure --prefix=/usr/local --mandir=/usr/local/man
make
make install

./autogen.sh
./configure
make
make install

Goto Wiki and enjoy the LTFS.

Please read CONTRIBUTING.md for details on our code of conduct, and the process for submitting pull requests to us.

This project is licensed under the BSD License - see the LICENSE file for details