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Backup Services

Our Commitment to Your Data

Data is precious! The ODU CS Department is committed to ensuring that the data of department faculty, staff, and students is protected. We employ a multi-layered approach to keep your data safe and recoverable.

How We Protect Your Data

The CS Department utilizes a combination of on-disk snapshots and off-site tape backups for comprehensive data protection.

On-Disk Snapshots (for recent file recovery)

NetApp Storage Snapshots

We use NetApp storage appliances to store user data (primarily your Unix home directory / Windows Z-Drive). These systems have a powerful snapshot feature enabled, which creates point-in-time copies of your data. These snapshots are invaluable for quickly recovering files that were recently modified or accidentally deleted.

Current Snapshot Retention Policy:

  • Hourly Snapshots: 5 snapshots are kept, taken at various intervals throughout recent hours.
    • These are typically for very recent changes within the last few hours.
  • 6-Hourly Snapshots: 28 snapshots are kept, taken approximately every 6 hours.
    • This provides coverage for roughly the past 7 days.
  • Weekly Snapshots: 26 snapshots are kept, taken once per week (e.g., Sunday night).
    • This allows for recovery going back approximately 6 months.

This tiered snapshot schedule provides a good balance between granular recovery for recent changes and longer-term retention for less recent modifications, all directly accessible from the storage system.

Tape Backups

Long-Term Tape Archives

In addition to on-disk snapshots, all user data on our central storage systems is backed up to tape media monthly.

  • Retention: These tape backups are retained for a minimum of 2 years.
  • Purpose: Tapes provide a robust, long-term archival solution and are a crucial component of our disaster recovery plan.
  • Recovery Speed: While very reliable, recovering data from tape is a slower process compared to snapshot recovery, as it involves retrieving the physical tape and restoring the data.

Recovering Your Data

The method for recovering data depends on how long ago the file was lost or modified.

Recovering Data Within the Last ~6 Months (Using Snapshots)

If the file was deleted or modified relatively recently (within the retention period of our snapshots, roughly up to 6 months), you can often recover it yourself directly.

On Unix/Linux Systems:

  1. Navigate to the directory where the file or folder used to reside: 
    cd /path/to/your/directory
  2. Change into the hidden .snapshot directory. This directory is special and contains the read-only snapshot copies: 
    cd .snapshot

  3. List the contents of the .snapshot directory. You will see a list of directories, each representing a snapshot. The names typically indicate the type and timestamp of the snapshot. 

    ls -l
    !!! example "Snapshot Naming Example"

    *   `hourly.YYYY-MM-DD_HHMM`
*   `six_hourly.YYYY-MM-DD_HHMM`
*   `weekly.YYYY-MM-DD_HHMM`

  4. Navigate into the snapshot directory that corresponds to a time before your file was deleted or undesirably changed. For example: 

    cd weekly.2023-10-22_0010

  5. Once inside the snapshot directory, you can browse its contents (which represent the state of your files at that point in time) using ls.
  6. When you find the file(s) you need, copy them back to your desired location in your live home directory. Do not try to modify files within the .snapshot directory as it's read-only. 
    cp my_lost_file.txt /path/to/your/live_directory/

On Windows Systems (Accessing Z-Drive Snapshots):

  1. Open File Explorer and navigate to the folder on your Z-Drive where the file or folder used to reside.
  2. Right-click on the folder (or a blank space within the folder if you're looking for a file that was in the root of that folder).
  3. Select "Properties" from the context menu.
  4. Go to the "Previous Versions" tab.
  5. You will see a list of available versions of that folder from different dates and times, corresponding to the snapshots.
  6. Select a version from a time before your file was lost or changed.

  7. You have several options:

    • Open: Browse the contents of the folder from that snapshot. You can then copy individual files/folders out to your live Z-Drive location.
    • Copy...: Copy the entire selected older version of the folder to a new location.
    • Restore...: This will attempt to replace the current live folder with the selected older version. Use with caution, as it will overwrite any changes made since that snapshot. It's often safer to "Open" or "Copy" and manually retrieve what you need.
Recovering Data Older Than ~6 Months (Requesting Tape Restore)

If the data you need to recover is older than what is available via the on-disk snapshots (generally older than approximately 6 months, up to 2 years old), you will need to request a restore from our tape backups.

  1. Please send an e-mail to root@cs.odu.edu.
  2. In your email, clearly specify:
    • The full path(s) to the file(s) or folder(s) you need to be recovered.
    • The approximate date (and time, if known) from which the data should be restored (i.e., the last known good state of the file).
  3. The Systems Group will then locate the relevant tape and initiate the restore process. Please be aware that tape restores can take significantly longer than snapshot restores.

Important Scope Limitation

The backup and recovery policies described above only apply to data stored within your CS Unix home directory and your corresponding Windows Z-Drive. Any files or information stored directly on the local C: drive of individual lab desktops, personal laptops, or in temporary folders are NOT backed up by the CS Department and can be permanently lost. Always save important work to your Z-Drive.