The Data Capacitor, Data Capacitor II, and DCWAN high-speed file systems at Indiana University
Note: Indiana University is in the process of
replacing its current Data Capacitor storage system with Data
Capacitor II (DC2), a high-speed, high-capacity, storage facility for
very large data sets. The DC2 file system
/N/dc2/scratch) is currently mounted on Big Red II,
Quarry, and Mason. Both systems (Data Capacitor and DC2) will be
available until December 3, 2013, when any data remaining on the Data
Capacitor scratch file system (
/N/dc/scratch) will be set
to read-only. On January 7, 2014, any data remaining on the Data
Capacitor will be deleted, and the system will be
decommissioned. Project directories on the Data Capacitor will be
migrated to DC2 (and their owners contacted) by UITS. Scratch
directory data will not be automatically migrated to
DC2. You should move any critical data stored in your Data Capacitor
scratch directory to the Scholarly Data Archive (SDA) as soon as
possible. For instructions on using the Hierarchical Storage Interface
(HSI) application to move your data, see At IU, how do I use HSI to access my SDA account? If you
have questions email the High
Performance File Systems group.
On this page:
- System overview
- System information
- System access
- Transferring files
- Usage policies
- Storing electronic Protected Health Information (ePHI)
The High Performance File Systems unit of UITS Research Technologies operates three separate high-speed file systems for temporary storage of research data. Each uses the open source Lustre parallel distributed file system running on a version of the Linux operating system:
Data Capacitor: The Data Capacitor is a
large-capacity, high-throughput, high-bandwidth file system serving
all IU campuses. It is available on IU's Big Red II,
Quarry, and Mason research computing systems.
Data Capacitor II: Data Capacitor II (DC2) is
larger, faster replacement for the Data Capacitor. Like its
predecessor, DC2 is a large-capacity, high-throughput, high-bandwidth
Lustre-based file system serving all IU campuses, available on the Big
Red II, Quarry, and Mason research computing systems.
- Data Capacitor wide-area network: The Data Capacitor wide-area network (DCWAN) is a large, high-speed data storage facility serving all IU campuses and several research centers throughout the nation. The DCWAN lets researchers access remote data as if that data were stored locally, making it easy to share large amounts of data among researchers at multiple remote sites.
Note: The Data Capacitor file systems are not intended for permanent storage of data, and are not backed up. Files in scratch space may be purged if they have not been accessed for more than 60 days. Files in project space may be purged if they have not been accessed for more than 180 days.
- The Data Capacitor is mounted on Big Red II, Quarry, and Mason as
/N/dc/, and behaves like any other disk device on those machines. If you have an account on Big Red II, Quarry, or Mason, you can access your Data Capacitor scratch directory at (replace
usernamewith your IU Network ID username): /N/dc/scratch/username
- Data Capacitor II (DC2) is mounted on Big Red II, Quarry, and
/N/dc2/, and behaves like any other disk device on those machines. If you have an account on Big Red II, Quarry, or Mason, you can access your DC2 scratch directory at (replace
usernamewith your IU Network ID username): /N/dc2/scratch/username
- Users at other institutions (including IU researchers with
accounts on remote systems) can request Data Capacitor WAN (DCWAN)
storage space, which can be mounted on remote systems, as well as on
Big Red II, Quarry, and Mason, as
The Data Capacitor file systems are parallel high-performance file
systems. Files are not "transferred" to a Data Capacitor
file system; instead the Data Capacitor file systems (Data Capacitor,
DC2, or DCWAN) are mounted on computational resources and are
accessible from those resource as directory paths (e.g.,
/N/dc2/scratch/username). To read or write a file on one
of the Data Capacitor file systems, use the same standard
Unix commands used for reading and writing files stored on
your computational system's local directories.
- The Data Capacitor file space is divided into two
Scratch: The scratch directory is a temporary
workspace currently available to all users of Big Red II, Quarry, and
Mason. Scratch space is not allocated, and its total capacity
fluctuates based on project space requirements. Files in scratch space
may be purged if they have not been accessed for more than 60 days.
Your personal scratch directory is automatically created with your user account. It is available at these locations, depending on the file system (replace/N/dc/scratch/username /N/dc2/scratch/username /N/dcwan/scratch/username
usernamewith your IU Network ID username):
Project: Project space is dedicated to long-term
projects with storage and access requirements that cannot be met by
other systems. Requests for project space will be submitted to the
High Performance File System team, and evaluated by the allocation
committee. Files in project space may be purged if they have not been
accessed for more than 180 days.
To request project space on the Data Capacitor, fill out and submit the Project Allocation Request Form.
- Scratch: The scratch directory is a temporary workspace currently available to all users of Big Red II, Quarry, and Mason. Scratch space is not allocated, and its total capacity fluctuates based on project space requirements. Files in scratch space may be purged if they have not been accessed for more than 60 days.
- File system space not allocated to projects will be available as
scratch space and will vary depending on file system usage.
- Projects receive a default quota of 10 TB. Project owners can
request quota increases if additional space is needed. Due to
performance issues, storing a large number of small files is
discouraged, but arrangements can be made if a need exists.
- The Data Capacitor file systems are not intended for permanent
storage of data and are not backed up. It is your responsibility to
arrange any long term storage required of any data on the Data
Capacitor file systems. At IU, to archive data stored or created on
the Data Capacitor file systems, move them to IU's Scholarly Data
- Lustre is not designed for storing a large number of small
files. If you need such storage, you should use a compression utility
gzip) to bundle your files into a small number of large files. Failure to do so can negatively impact performance of the Data Capacitor file systems and strain their file-count (inode) capacities.
Storing electronic Protected Health Information (ePHI)
If you use the Data Capacitor or Data Capacitor II file system to store electronic Protected Health Information (ePHI), you and/or the project's Principal Investigator (PI) are responsible for ensuring the privacy and security of that data, and complying with applicable federal and state laws/regulations and institutional policies. IU's policies regarding compliance with the Health Insurance Portability and Accountability Act of 1996 (HIPAA) require the appropriate Institutional Review Board (IRB) approvals and a Data Management Plan.
Note: Storing ePHI on the DCWAN file system is not permitted.
Although UITS Research Technologies provides technical and physical controls against the unauthorized release of data in accordance with HIPAA, responsibility for administrative controls (including granting and terminating access, providing training, and creating user policies), rests with you and/or the PI.
To ensure that your Data Capacitor or Data Capacitor II directory is accessible only by you, use Unix permissions to restrict access:
- To change the permission of an existing file or directory, use the
chmodcommand. For example, to restrict all read and write access to the owner of
ephi_file, on the command line, enter: chmod 700 ephi_file
The above command will set the Unix permissions to look like this: -rwx------ 1 <username> uits 40 Sep 13 15:12 ephi_file
- To configure your user environment so that every new file and directory gets the same permission level (accessible only by the owner), add the following line to your shell profile: umask 077
For more about setting permission in Unix, see:
- In Unix, how do I change the permissions for a file?
- In Unix, how do I set the default protection to newly created directories and files?
For more about the Lustre file system, see the Lustre wiki.
For technical support or general information, email High
Performance File Systems. For after-hours support, call Data
Center Operations (812-855-9910) and ask to have High Performance File
Systems contacted. To receive maintenance and downtime information,
subscribe to the
list (see On IU List, how do I subscribe to a list?).
Last modified on November 11, 2013.