Snapshots and replication

What is replication?

  • Replication is the process of making (and maintaining) an identical duplicate copy from one storage system to another. In the case of Turbo, replicated copies are sent offsite to provide data integrity, site redundancy, and increased availability for Turbo data in the event of a systems outage.

 

What are Snapshots?

Snapshots are a tool provided by Enterprise Storage Systems, such as Turbo, that provide point-in-time rollback for any files/folders that are changed or deleted. Snapshots catalog changes to files/folders (on a nightly basis) and maintain copies of any files that were changed or deleted since the last snapshot. So, if a file is accidentally deleted, it may be recoverable through the previous days’ snapshots.

  • Snapshots can be requested at no additional charge, although the snapshots will count against your available capacity.
  • Your snapshots can be found in /nfs/turbo/<volume_name>/.snapshots/
  • Snapshots are available with the following options:
    • Daily snapshot, retained for 7 days (default, if selected)
    • Daily snapshot, retained for 1 day
    • Daily snapshot, retained for 3 days
    • Daily snapshot, retained for 7 days, and 1 bi-weekly snapshot
  • Snapshots are taken on a nightly basis, so if a file is created and deleted on the same day, it may not be recoverable.
  • Note: If a large volume of files are changed or deleted in a short period of time; the snapshots may consume a considerable amount of one’s allocated capacity.
  • If you suspect snapshots are taking up too much space; please contact arcts-support@umich.edu and we would be happy to help resolve the issue

Recovering lost files

Turbo volumes that are configured with snapshots will save previous versions of files.  Only files which have been snap-shotted overnight are recoverable.  Files that are lost on the same day they were created may not be recoverable.

From Linux based clients: To recover files lost from your directory, navigate to the .snapshot directory at the root of your share.

$ cd /nfs/turbo/flux-admin/.snapshot
$ ls -1
daily_2015-08-24-_23-30
daily_2015-08-25-_23-30
daily_2015-08-26-_23-30
daily_2015-08-27-_23-30
daily_2015-08-28-_23-30
daily_2015-08-29-_23-30
daily_2015-08-30-_23-30

You can navigate to the snapshot directories and copy files back to your file share.
Note: The .snapshot directory may not be visible until you try enter it with cd.

From Windows clients, you can recover lost files from snapshots natively:

  • Open the directory that the deleted file was held in.
  • Right click in the directory that the file or folder was stored and select “Properties”.
  • Click on the “Previous Versions” tab when the Properties window opens.
  • A list of snapshots will be displayed.
  • Select the snapshot from which you wish to restore data.
  • In the new window, locate the file(s) you wish to restore.
  • Simply drag the file(s) or folder to their correct locations

Leave a Reply