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File Systems on Ram

Contents

• Home Directory
• Global Work Space
• High-Performance Storage System (HPSS)

Home Directory

User home directories as well as some system directories are located in a Network File Service (NFS).

Because the NFS servers are outside Ram, NFS does not provide the highest performance. For fast file access on Ram, see "Global Work Space", below.

Each user has a default storage limit of 500 MB in their home directory. In addition to the ".yesterday" backup described below, home directories in NFS are copied to tape backup four times a week.

To find your quota and usage in NFS, use the following command

$ lsquota
Fileset Name          Quota    Used  Used   Aggregate
us.user               500000  407726    81%    89% = 22865076/25574421
(LFS)

Each home directory has a default set of subdirectories:

public	This directory is world readable. Use it to make files available to other CCS users.
private	This directory is only accessible by the user.
.yesterday	This directory contains a read-only copy of all the rest of the home directory, including other subdirectories, as of the day before. The copy is generated at 4AM each morning. If you accidentally delete any of your NFS files, you can simply copy versions from the day before out of ".yesterday". You cannot directly create or remove files from the yesterday directory.
bin	This directory is a location for user-generated executables. It is not in your "PATH" by default, however. You can add it or one if its subdirectories to your "PATH" in your ".profile" or ".cshrc" file.
www	Documents kept in this directory are available over the World-Wide Web provided the permissions allow readability. These files can be accessed from http://www.ccs.ornl.gov/~user.

Global Work Space

Global work space is available on Ram for temporary files used across multiple nodes and for staging large files from and to HPSS. The space is not backed up, and it may be purged to help ensure that adequate work space is available for new jobs. Files that have not been accessed for more than a week are considered eligible for purging.

The following area is available.

/tmp/work/$USER

Each user has a directory in "/tmp/work" created for them with a 300 GB quota when their accounts are created. This is intended as work space for Ram applications. This area is not backed up, so you need to copy any important output to one of the other file systems for permanent storage. This area is also purged on a regular basis to help ensure that adequate work space is available for new jobs. Files that have not been accessed for more than a week are considered eligible for purging.

Do not use "/tmp" for temporary storage of files. When "/tmp" fills up, system problems result.

High-Performance Storage System

The High-Performance Storage System (HPSS) provides archival storage. It is "high performance" relative to other archival systems, not relative to native file systems. Large permanent files should be moved directly from $SYSTEM_USERDIR, presumably where they were created, to HPSS.

You access HPSS through the "hsi" interface, which is available on Ram. Because it uses Kerberos authentication, "hsi" requires no password and can thus be used within batch scripts. The CCS is moving to one-time passwords (OTPs) for authentication. Once this occurs, "hsi" will require an OTP for each connection, so it will no longer work within batch scripts. Please contact "consult@ccs.ornl.gov" if you need password-free access to "hsi" on Ram.

For more information on HPSS and "hsi", type "hsi help" on Ram or see the online documentation, available at the following URL.

http://www.ccs.ornl.gov/Storage/hsi_docs/

HPSS is unavailable during maintenance, which typically occurs Wednesday mornings, about 7-10 AM ET.