If you use LTO-5 (or later) tape media, you can choose to store archive copies in the traditional native StorNext tape format (ANTF) and/or in Open LTFS tape format. For complete details on supported libraries and drives, see the StorNext 6 Compatibility Guide.
For details on LTFS limitations, see the StorNext 6 Compatibility Guide.
The LTFS tape format offers most of the same functionality as the ANTF format with the additional benefit of being portable. That is, tape media in LTFS format by can be vaulted and removed from the StorNext Storage Manager system and mounted elsewhere using the freely available Open LTFS package, allowing access to the data without requiring any additional software from Quantum.
The StorNext implementation for LTFS is based on the Open LTFS Format Specification v 2.2.1 and is compatible with implementations from other vendors at or above this version.
StorNext for LTFS includes support for the following features:
- Policy-class-copy steering by media format type for LTO tape media
- Automatic media selection and formatting
- Distributed data mover support
- File versioning on LTFS media
- File recovery from LTFS media
- LTFS media defragmentation
- Tape-to-tape copy from ANTF to LTFS, and from LTFS to ANTF
- Import of native LTFS media into StorNext
- Export/import of StorNext managed LTFS media
Features NOT supported in StorNext for LTFS:
- Segmented files
- LTFS volume spanning
- StorNext backup to LTFS
Access of StorNext-generated LTFS media outside of StorNext (for example, by an Open LTFS package,) should be considered read-only.
Be aware that a StorNext-generated LTFS medium may be rendered unusable within StorNext if it is modified outside of StorNext. If the medium is required for data retrieval of truncated files within the StorNext file system, access to those files may not be possible if the medium is modified outside of StorNext.
Exporting and importing LTFS media allows you to move data out of one system and into another.
At a Glance: Exporting LTFS Media
- Media is removed from the system on export, and files are optionally removed from the file system.
- When a copy of the media is exported, only active file copy versions are exported.
- Any media that is exported can also be imported.
Use either the Export Media or Export Copy of Media action in the StorNext GUI to export storage media that contain file data from the Tertiary Manager system. After the export, the media can be physically removed, either by using Media Manager commands or by using the Library Operator Interface (LOI) in the StorNext GUI. After media are exported from one Tertiary Manager system, they may be imported into another Tertiary Manager system using the Import Media action.
Note: The Tertiary Manager system does not support LTFS segmented files.
At a Glance: Importing LTFS Media
- You can import everything that is exported.
- You can optionally scan content from other systems that use LTFS format.
Media Ingest versus File Ingest: A Media Ingest operation permanently imports media and its contents into the system, whereas a File Ingest operation imports the contents of the media and removes the media from the system at the end of the import process.
When media is imported, it is marked as Write Protected to avoid key collisions in a Tertiary Manager database.
To write to imported media, execute the fsmedcopy command to move the contents from the imported medium to another medium. The imported medium reverts to a blank status after the contents are copied.
For additional information, see the commands fsexport(1) and fsimport(1) in the StorNext Man Pages Reference Guide.
Now that two different media formats (ANTF/LTFS) are supported for LTO media in StorNext, you should keep in mind some points about configuration and usage to make the best choices for your StorNext environment.
In the Steering tab in the Storage Manager Policies configuration page, in the Media Format list, you can select either ANTF or LTFS formats for the LTO (tape) Media Type.
Note: This only applies to tape formats; there are no Media Format selections available for either Object Storage or Storage Disks.
LTFS appears in the Configuration > Storage Manager Policies > Storage Manager tab (in the Steering column), and in the View page (in the Media Format column).
The LTFS media format also appears in the Reports > Media page (in the Media Format column).
Additional checks have been included in the StorNext Linux-based installation to ensure that some additional RPM packages required to support the LTFS media format are installed prior to installing StorNext. For additional LTFS requirements, see the StorNext Compatibility Guide, the StorNext Installation Guide, and the StorNext Upgrade Guide.
Following is a list of these items to consider:
- StorNext Storage Manager LTFS support is based on LTFS Format Specification v 2.0.0. The LTFS Format Specification does not support backwards compatibility with earlier versions of the specification.
The LTFS Format Specifications v 2.0.0 and v 2.2.1 are compatible with each other. If a tape is formatted with version v 2.0.0 and is written to by StorNext, the tape format will be upgraded to v 2.2.1. Similarly, a tape formatted with version v 2.2.1 will be downgraded to a v 2.0.0 if it is written to by a release prior to StorNext 5.4.0.
- Neither LTFS Format v 2.0.0 nor v 2.2.1 provides a means for maintaining file ownership and permissions when storing files to LTFS media. Ownership and permissions are managed at LTFS file system mount time using options passed to the Open LTFS package commands. When media formatted with LTFS v 2.0.0 or v 2.2.1 is used within StorNext Storage manager, access is restricted to the root user and the tape is not accessible outside of the StorNext Storage Manager processes. When the media is mounted outside of StorNext Storage Manager, care should be taken to ensure that proper access permissions are used when the LTFS volume is mounted.
- Storage Manager does not support segmented files for LTFS. This includes files being stored as well as files being copied from tape to tape (
fsmedcopy). To manage this, the configuration parameter
DEF_MED_SPC_LTO_LTFSin the file
/usr/adic/TSM/config/fs_sysparmcan be used to specify the maximum file size that can be stored to LTFS media.
- StorNext supports a maximum tape block size of 1MB for LTFS. To manage this, the configuration parameter
FS_LTO_LTFS_BLOCK_FACTORin the file
/usr/adic/TSM/config/fs_sysparmcan be used to calculate the LTFS tape block size and limit it to 1MB for LTFS formatted media.
- LTFS allocates at least one tape block for each file, and no two files share the same tape block. Therefore, every file consumes an amount of space on tape that is a multiple of the tape block size. As a consequence, very small files do not make efficient use of tape capacity, especially when large tape block sizes are configured.
- StorNext Backup (_adic_backup policy class) is not supported for LTFS.
- Because LTFS is a file system on a tape, additional overhead is incurred when Storage Manager processes have to mount and unmount the LTFS file system. Because of this, ANTF will outperform LTFS in most situations. Therefore, StorNext users SHOULD NOT configure LTFS for the primary copy used for file retrieval (for example, copy 1).
- To minimize this additional overhead, system parameters should be configured to process high file counts and high byte counts for store and retrieve requests. The configuration parameter MAX_FILES_PER_CLUSTER in the file /usr/adic/TSM/config/fs_sysparm should remain at the default of 3000 and not be reduced. The undocumented configuration parameter FS_CLUSTER_LIMIT_LTO in the file /usr/adic/TSM/config/fs_sysparm should be increased to 1,000,000,000,000 (1TB) for LTO-L5 media, 2,000,000,000,000 (2TB) for LTO-L6 media, 6,000,000,000,000 (6TB) for LTO-L7 media, 9,000,000,000,000 (9TB) for LTO-M8 media, and 12,000,000,000,000 (12TB) for LTO-L8 media. The FS_CLUSTER_LIMIT_LTO parameter should be set to the lowest recommended LTO generation value in environments where multiple LTO generations are being used with LTFS.
- The amount of metadata stored in the LTFS index partition grows as files are added to an LTFS volume. This metadata is always loaded into the fs_fmover process memory when the LTFS volume is mounted, and continues to grow as files are added to the LTFS volume. This means that memory requirements for the fs_fmover process are larger when the source and/or destination media format type is LTFS as compared to when the source and destination media format types are both ANTF.
The LTFS standard prohibits the use of the following characters in directory and file names:
- : (colon)
- / (slash)
WARNING: Attempting to store files to LTFS that have prohibited characters in directory or file names in the path will fail and cause an admin alert to be generated.
These files will then be removed from the store policy candidate list by having the
FS_NO_STOREflag set in the file attributes. To successfully store these files, they must be renamed to no longer contain any prohibited characters in any of the directory or file names in the path. After the files have been renamed, you must clear the
FS_NO_STOREattribute flag using the
fschfiat -spcommand or the Tools > File and Directory Actions > Modify File Attributes GUI page so that the policy can place the files back on the store candidate list. Keep in mind that all future file modifications will be ignored and no additional copies will be made of these files, regardless of media type or format, until the
FS_NO_STOREattribute flag has been cleared.
WARNING: Quantum recommends that you avoid using certain characters for interoperability between operating systems. Do not use the following characters in either directory or file names if the files are to be stored to LTFS media:
- * (asterisk)
- ? (question mark)
- < (left angle quote)
- > (right angle quote)
- " (quotation mark)
- | (vertical bar)
- \ (backslash)
While not prohibited on Linux or macOS, you cannot use these characters on Windows because of additional restrictions for characters used in directory and file names.