Thayer Backups

All files on the ThayerFS and Jumbo file systems are backed up online to disk. Details of these backup methods are below:

Online Backups

Online backups of our file system are done automatically by our file system software using a technology called "Snapshots." These read-only snapshots of the state of all folders and files at a particular instant in time are taken on a fixed schedule and can be accessed easily during the retention period to recover either old versions of files or deleted files.


In the case of jumbo directories, the amount of snapshot space is limited to 20% of the directory quota - this additional space is provided above and beyond what is purchased. So, if large volumes of data are created and deleted repetitively in your directory, you may easily exceed the amount of space allocated to snapshots. Once the used snapshot space exceeds 90%, the oldest snapshots will be deleted until the free snapshot space reaches 10%, resulting in fewer snapshot copies. Even in this case, the disk backups described below will not be affected, and Computing Services can retrieve backups if it is ever necessary.


Currently, the schedule for our online backups is:

  • ThayerFS
    • Every two hours (e.g 2:00am, 4:00am, etc.) - up to the most recent twenty-two are retained
    • Every night at 12:00am - up to the most recent nine are retained
    • Every Sunday at 12:00am - up to the most recent fifteen are retained
  • Jumbo
    • Every night at 12:00am - up to the most recent fourteen are retained

How to retrieve backups

Retrieving backup data from Snapshots requires connecting to ThayerFS or Jumbo in a slightly different way than you may be used to. Please make sure to read and follow the instructions below closely.


  1. Open File Explorer - click Start and begin typing "File Explorer" until you see and can click on the File Explorer icon.
  2. Navigate the folder that contains (or contained) the data you wish to restore.
  3. Right-click on any file or folder, select Properties... and then click the Previous Versions tab.

    In this tab, you will see the dates and times of all the previous versions of the file or folder that exist. For example, a file that had not changed since the oldest snapshot will not have any previous versions since all the snapshots are newer than one week old.

  4. You can choose to either Open or Restore one of the previous versions.
    • If you Open a previous version of a file, it will open in it's associated application. Opening a previous version of a folder will show you a view of what the folder looked like when the snapshot was taken. You can then select a file or files to copy out to another location.
    • If you select Restore, the previous version of the file or folder will completely replace the current version - use care with this option; it cannot be undone.


ThayerFS snapshots cannot be accessed from macOS. In order to view or retrieve snapshots, please use Windows or Linux. One easy way to do this from macOS is using the  Virtual Computer Lab.

The instructions below apply to snapshots on Jumbo only.

  1. From the Finder, select the Go menu and choose Connect to Server...
  2. Type in a server address like:

    where your_netid is your Dartmouth NetID and myfolder is the Jumbo folder that you need to access.

  3. Click the Connect button. If prompted, enter your Dartmouth password. This will mount the specified snapshot folder directly which you can then access from the Finder.
  4. In the root of the volume you have just mounted, you will find up to fifteen sub-folders:

    • GMT-YYYY.MM.DD-04.00.00 - these are the snapshots taken each night at midnight, identified by date
  5. To retrieve a file, copy it from the appropriate snapshot folder to a location outside the snapshot tree.


From one of our Linux clients, you can access snapshots on both ThayerFS and Jumbo.


For ThayerFS folders, there is a hidden .snapshot folder at any level in the directory tree. This folder contains all available snapshots for that folder, with timestamps to indicate when they were taken. Any files or folders can be copied from these snapshots to a location in the live filesystem.

For example, to restore an important file from last night's daily snapshot:

cp ~/Documents/.snapshot/thayerfs-daily_2018-07-18-_00-00/important ~/Documents/

On Jumbo, there is a hidden .zfs/snapshot folder at the root of every volume. This folder contains all available snapshots for that folder, named with timestamps of when they were taken. Any files or folders can be copied from these snapshots to a location in the live filesystem.

For example, to restore an important file from last night's daily snapshot:

cp /jumbo/research_group/.zfs/snapshot/GMT-2018.07.18-04.00.00/group_1/project_5/important  /jumbo/research_group/group_1/project_5/

Remote Backups (not user accessible)

Disk-based backups of our file servers happen every morning between midnight and noon.

At this time, there is no way for a user to retrieve a file or files from the offsite backups. If a file needs to be retrieved from these backups, please e-mail with as much detail as possible (file name or names, file location(s), date(s) of file needed and/or deletion date of the file) and we will attempt to retrieve the file or files within one business day.

Backup Retention Policy

By policy, Computing Services does not retain backups for more than 100 days.

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