File Systems on Ram
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
Fileset Name Quota Used Used Aggregate
us.user 500000 407726 81% 89% = 22865076/25574421
Each home directory has a default set of subdirectories:
||This directory is world readable. Use it to make files available to
other CCS users.
||This directory is only accessible by the user.
||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.
||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.
||Documents kept in this directory are available
over the World-Wide Web provided the permissions allow readability.
These files can be accessed from
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.
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.
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,
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
"email@example.com" 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
HPSS is unavailable during maintenance, which
typically occurs Wednesday mornings, about 7-10 AM ET.