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File Backups

1-Day and 2-Day Mirrors

As mentioned on the introduction page we have backups of home directories from 1 day before and from 2 days before on disk. All home directories are copied at 3AM to the 1-Day mirror. Before that (at 8PM) the 1-Day mirror is copied to the 2-Day mirror. So in effect there is a snapshot of your home directory as it was at ~3AM today and as it was at ~3AM yesterday.

To retrieve data from the 1-Day mirrors simply do:

cd /users/username-mirror

where username is your username. Then copy this data from here to your home directory.

NOTE WELL: Do not modify files on the mirrors.

If you have lost data that was in your home directory 2 days before (that is not on the previous day's mirror), you can get it from the 2-Day mirror.

To retrieve data from 2-Day mirrors:

1. All of the 2nd mirror data is contained on a disk on miele, so you need to login to miele by doing:

ssh -l username  miele.physics.lsa.umich.edu

2. On miele, to get to your data do:

cd /1a/data/mirror/cscs01/users/username

where you replace 'username' with your login. Then just copy the important files from here to your home directory.

NOTE WELL: Do not modify files on the mirrors.

If any of these steps are unclear contact cscs.admins@umich.edu and we can help you retrieve the files.

Tape backups

As mentioned on the introduction page we do backups of user data to tape weekly (every friday night). If you lost important data that would have been backed up on the previous week's tape and it is not on the 1 day or 2 day mirrors, contact the cscs.admins@umich.edu and we can retrieve this data for you.

We cycle through the weekly filesave tapes about every 12 weeks. Thus if a file is on the system on any friday night in the last 3 months, you can ask us to retreive it. Every four months, we also save the weekly filesave tape "forever". So if you need to retrieve a file from over 3 months ago, we can do that if it was on one of the tri-annual permanent-save tapes.

Scratch Disk Space

These disks are mirrored daily to protect the data in case there is a disk failure. If there is a disk failure on a scratch disk or you suspect a disk failure, please contact cscs.admins@umich.edu and we will retrieve your data and get the disk back up and running for you.

For more information on using the CSCS scratch disk space please check out our scratch disk page.

For more information about using the scratch areas for storing simulation output (e.g., from drone experiments) see our page on how to run drone experiments.

Updated September 1, 2005