CHTC /staging and /projects Next Steps

On Thursday, November 21, CHTC personnel were alerted to data issues in our /staging and /projects directories. We took immediate action on Thursday afternoon and have been working on mitigation and data recovery since.

The underlying cause has been identified and affected the /squid, /staging, /projects and HTC /software directories. We are able to prevent it from recurring; however, it resulted in significant data loss in /staging, /projects, HTC /software and /squid before CHTC personnel were able to react. All data in /squid is unrecoverable. Data recovery on /staging is complete as of mid December 2024; Data recovery on /projects is complete as of mid January 2025.

We recognize that this outage and accompanying data loss is disruptive to important work. Our plan to bring systems and data back online is outlined below.

User Next Steps

Resume Running Jobs

All HTC users should now have access to a empty /staging directory with a default quota of 100GB / 1000 items. This space can be used exactly like the previous /staging directories to run jobs (See our staging guide).

A few notes about special circumstances:

• Group and project directories: Group and project directories will need to be created manually – contact the facilitators at chtc@cs.wisc.edu or fill out our quota request form to have a group directory created.
• Quota changes: Quotas from the previous file system will not transfer over, so if you anticipate needing space beyond the default quota, especially in the short term, please fill out our Quota Request Form
• Immediate deadlines: If you have a short-term deadline (within the next 2-3 weeks) please reach out to see how we can support you. Email chtc@cs.wisc.edu with the following:
  • Include your name and the deadline date in the subject line
  • Cc your PI or advisor
  • Describe the nature of the deadline (paper submission, thesis defense, conference deadline, etc.)
  • Describe what specific computational or data capacity you need in order to meet the deadline (how many jobs, how many resources per job, how much data, etc.)

Access Recovered Data

Recover /staging and /software data

The data recovery process for /staging and /software was completed on 12/11. We believe we have recovered about 50% of the data that was originally present in these directories. Some of the metadata for files (like file creation date) may be incorrect; we strongly recommend validating any data that you copy from the recovered file system.

Any recovered data is available at this path:

• /recovery/staging/<your username>
• /recovery/software/<your username>

Users should copy any recovered files they want to save into their new /staging directories.

References to data using the paths to recovered staging directories should not be used in job submission. The directories for recovered data are read-only, and you will not be able to write into them.

If your directory doesn’t exist in the recovery path, that means that none of your data was recovered.

Recover /projects data

The data recovery process for /projects was completed on 1/10. We believe we have recovered most, if not all, of the data that was originally present in these directories. Some of the metadata for files (like file creation date) may be incorrect; we strongly recommend validating any data that you copy from the recovered file system.

Any recovered data is available at this path:

• /recovery/projects/<project-name>

Users should copy any recovered files they want to save into their new /projects directories.

References to data using the paths to recovered staging directories should not be used in job submission. The directories for recovered data are read-only, and you will not be able to write into them.

If your directory doesn’t exist in the recovery path, that means that none of your data was recovered.

CHTC Next Steps and Timeline

• Nov 25 - 27: New data backend for /staging and /projects
  • During the week of Nov 25-27, we created a new data store to serve the /staging and /projects directories. Initially, there is no data inside these directories. This new data backend for the /staging and /projects directories will be used for CHTC data storage moving forward and is usable in jobs immediately.
• Nov 25 - Dec 10: Recovering data from /staging directories
  • We have run multiple recovery processes on the old data store. Once each recovery process is complete, CHTC users will be able to access recovered data and copy it to the new data store. CHTC will not overwrite or replace data created in the meantime. See above for more details.
• Dec 11 onward: Recovering data from /projects
  • This will be the same process as recovering data from /staging.
• Jan 13: Recovered data from /projects available
  • Data recovery for /projects is complete. See above for more details.

Stay Informed

In order to find out when the new file system is available and when recovered data is available, we recommend following the relevant incident(s) on the CHTC status page. You can subscribe to the status page for the latest updates: https://status.chtc.wisc.edu/

This web guide will also be updated as changes occur.

Contact Us

We understand the challenge of restarting your work after an event like this. If you have any questions or specific concerns after reading through this guide, please contact us at chtc@cs.wisc.edu. We will do our best to help all CHTC users get up and running again as soon as possible.