Using HPSS

HPSS is a data archive and retrieval system that manages large amounts of data on disk and robotic tape libraries. It provides hierarchical storage management services that allow it to migrate data between those storage platforms.

HPSS is currently configured with a disk and tape tier. The disk tier has a capacity of 1.2PB on a DataDirect Networks SFA12K-40 storage array. By default, all archived data is initially written to the disk tier. The tape tier consists of 3 SpectraLogic T950 robotic tape libraries containing a total of 48 LTO6 tape drives with total uncompressed capacity 75 PB. Archived data is migrated to the tape tier at regular intervals, then deleted from the disk tier to create space for future archives.

Access to HPSS is provided by various client components. Currently, ALCF supports access through two command-line clients, HSI and HTAR.  These are installed on the login nodes of Theta, Mira, Cetus and Cooley. In order for the client to authenticate with HPSS, the user must have a keytab file that should be located in their home directory under subdirectory .hpss. The file name will be in the format .ktb_<userid>.

Documentation and user guides for HSI and HTAR can be found at the following links:

HSI General Usage

HSI can be invoked by simply entering hsi at your normal shell prompt. Once authenticated, you will enter the hsi command shell environment:

   > hsi
   [HSI]/home/username->

You may enter "help" to display a brief description of available commands.

Example archive

   [HSI]/home/username-> put mydatafile                # same name on HPSS
   [HSI]/home/username-> put local.file : hpss.file    # different name on HPSS

Example retrieval

   [HSI]/home/username-> get mydatafile
   [HSI]/home/username-> get local.file : hpss.file

Most of the usual shell commands will work as expected in the HSI command environment. For example, checking what files are archived:

   [HSI]/home/username-> ls -l

And organizing your archived files:

   [HSI]/home/username-> mkdir dataset1
   [HSI]/home/username-> mv hpss.file dataset1
   [HSI]/home/username-> ls dataset1
   [HSI]/home/username-> rm dataset1/hpss.file

It may be necessary to use single or double quotes around metacharacters to avoid having the shell prematurely expand them.  For example:

   [HSI]/home/username-> get *.c

will not work, but

   [HSI]/home/username-> get "*.c"

will retrieve all files ending in .c.

Following normal shell conventions, other special characters in filenames such as whitespace and semicolon also need to be escaped with "\" (backslash).   For example:

       [HSI]/home/username-> get "data\ file\ \;\ version\ 1"

retrieves the file named "data file ; version 1".

HSI can also be run as a command line or embedded in a script as follows:

   hsi -O log.file "put local.file"

HTAR General Usage

HTAR is a tar-like utility that creates tar-format archive files directly in HPSS. It can be run as a command line or embedded in a script.

Example archive

   htar -cf hpssfile.tar localfile1 localfile2 localfile3

Example retrieval

   htar -xf hpssfile.tar localfile2

NOTE:  The current version of HTAR has a 64GB file size limit as well as a path length limit.  The recommended client is HSI.

Globus

In addition, HPSS is accessible through the Globus endpoint alcf#dtn_hpss.  As with HSI and HTAR, you must have a keytab file before using this endpoint.  For more information on using Globus, please see Using Globus.

Common Problems

Keytab File Missing

If you see an error like this:

 *** HSI: (KEYTAB auth method) - keytab file missing or inaccessible: /
 home/username/.hpss/.ktb_username
 Error - authentication/initialization failed

it means that your account is not enabled to use the HPSS yet. Please contact support to have it set up.