Are the data stored on the MDSS backed up?

Due to the mammoth volume of data stored on the Massive Data Storage Service (MDSS) at Indiana University, it is neither practical nor economical to back it up, at least not in the usual sense. However, two tape copies of the data are made by default to protect against random tape errors. If one tape were to fail, data could be retrieved from the other tape. Unfortunately, since the files are always online and visible to the users, an accidental deletion means that data is irreversibly lost. The MDSS in this sense doesn't have an offline, traditional backup system.

The two copies of data stored on the MDSS reside at two geographically distant sites (at IU Bloomington and at IUPUI in Indianapolis), in two separate tape libraries. Also, two separate metadata backups are performed, at IUB and IUPUI. As a result, even if there were to be a catastrophic disaster affecting either the IUB or IUPUI site (such as a fire or a tornado), all dual-copy data on the system will still be safe.

This document was developed with support from the National Science Foundation (NSF) under Grant No. 0503697 to the University of Chicago and subcontracted to Indiana University. Additional support was provided by IU through its participation in the TeraGrid, which is supported by the NSF under Grants No. 0833618, SCI451237, SCI535258, and SCI504075. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the NSF.

Also see:

• At IU, on the RFS or MDSS, how much space is available to me?
• At IU, how do I access the MDSS?