GFDL Archive

The GFDL archive is a long-term archive system based on HPE’s Data Management Framework (DMF). The GFDL archive includes 13.1 petabytes of front-end disk cache, 5 tape libraries, and 160+ tape drives. Total available capacity is 360 PB. The GFDL archive is accessible from Pan and other GFDL systems.

Users should keep the following things in mind when using the GFDL archive system:

  • The GFDL archive is well suited for storing large volumes of data.

  • Users should avoid storing small files (in the megabyte range or smaller) to the archive since the process of moving numerous individual small files to and from tape is inefficient. Please tar up small files into one large tar file before storing data into the archive.

  • All data stored in the archive is single copy. Deleted data cannot be recovered.

  • The archive file system should not be used for direct file access. Users should copy files to one of the other Pan file systems prior to working with the file.

For questions regarding the HPSS system, email oar.gfdl.help@noaa.gov.

Gaining Access to use the GFDL Archive

All users with a GFDL account will have a personal archive directory.

GFDL Archive Data Structure

The users archive area is located at /archive/$USER. The /archive/$USER is a symbolic link to /arch[0-8bcfgh]/$USER. These arch[0-8bcfgh] directories are used to better distribute the load on the front-end cache drives.

All files are ultimately stored on tapes housed in the tape libraries, access to those files is using the Linux file system structure on the front-end cache. When a file is accessed, DMF will automatically recall the file from tape and place it on the front-end cache disk.

Data Retention

At this time files stored in the GFDL archive do not have a set retention policy. GFDL divisions and users can decide how long to keep files in the archive. However to ensure adequate space is available for all, uses should remove data that is no longer needed.

Data Recovery Policy

Occasionally an archive tape is damaged or otherwise becomes partially unreadable. When that happens, the local RDHPCS staff works with the manufacturer to troubleshoot the problem and take steps to attempt to recover the missing data. Very rarely, even with these efforts, we are unable to recover the missing files. The user will then be informed of the files we cannot recover.

In that case, the user has one further option. There are a number of outside recovery services which will make further attempts at recovery for a fee. Some charge a flat fee, some charge more if they are able to recover than if they are unable to recover. If the user wishes to sign up for such a service and pay the fee, RDHPCS will handle the logistics of shipping and other coordination with the recovery service.

Getting Started

The GFDL archive is accessible from all Pan nodes, including all DTNs, and via a Globus endpoint. The GFDL archive is also available as read-only from the GFDL workstations.

DMF has a few utilities to help manage files stored on in the tape library and their residency on the front-end disk cache. The list, with a brief description is in the table below. See man <command> for more information.

Commands

Description

dmget <files>

Recall files from tape to the front-end cache

dmput <files>

Write files to tape

dmwho

Show pending dmgets with wait times

dmls -l <files>

Show file state (disk/tape residence)

Warning

Files should be copied from /archive to the one of the other Pan file systems, e.g., /vftmp fast-scratch filesystem, before use.

Allocation and Quota

The GFDL director allocates tape storage to each GFDL group. A group leader may also set allocations for individuals in the group. These allocations, and the percent used, are shown by the local archrpt command:

archrpt -s archrpt -r <group>

These allocations are enforced administratively. For details, see archrpt -h.

Finding Files

To facility the ability for users to search for files in the GFDL archive, a database of file in the archive is updated daily. To search for files in the archive, supply a pattern to the dmlocate command:

$ dmlocate <pattern>

Refer to man dmlocate for more information.

GFDL Archive Help

For additional questions, please email: oar.gfdl.help@noaa.gov.