Data is precious! Consequently, the ODU CS Department ensures that the data of department faculty and students are backed up regularly. We employ a number of methods to keep data safe.
The CS Department uses EMC NAS/SAN storage devices to store user data. We have enabled snapshots on those devices that allow us to make copies of data that can be used to recover files that were shortly deleted.
The policy for snapshots is as follows:
- Three snapshots are taken at different times of the day: 6 a.m., 12 p.m., and 6 p.m. Those are only kept for 24 hours.
- Another set of snapshots is taken at 12 a.m. every morning and it kept for 7 days.
- A third set of snapshots is taken at 12 a.m. on Sunday night and kept for 1 month. This practice allows us to save copies of a file during the day, another copy from 12 a.m. every night and then a weekly copy for 1 month.
We also keep disk backups of all user data. The disk backups run at 12a.m. every night and are kept for 6 months. This allows us to restore data up to 6 months from the current date.
Tape Backups are the third backup resource we have. All user data is backed up monthly and stored for 2 years on tapes, to allow recovery of up to 2 years back. Tape recoveries are much slower compared to disk, but are very reliable.
Recovering Data Within the Last Month
- cd to the directory where the file used to reside.
- cd .snapshot
- You should see a list of backups where the name specifies the date the snapshot was taken. The format is as follows: every_6_hours.2018-08-10_1800 = This is a 6-hour incremental backup that was taken on 08/10/2018, at 18:00 hours.
- cd into the directory you need, and type ls. You will see the files you need.
- Directly copy the file into your home directory.
- Right click the directory where the file used to reside.
- Select Properties
- Select the Previous Versions Tab
- You will see a list of this directory from different dates in the past. You have the option to copy the entire folder to another location or just restore in the place it resides.
Recovering Data Older Than 1 Month
To recover data past 1 month, you must contact the Systems Group. Please send an e-mail to email@example.com with the files you want to be recovered, and the date to recover them from.
Note: The backup and recovery policies only apply to your Unix home directory/Windows Z-drive. Any other information on your local desktops will not be saved.