- Tape backups provide long term backup and archival and protect against multiple disk failure.
- RAID-5 protects against single disk failure without downtime and the loss of data since the most recent tape backup.
Filesystem snapshots are a new addition to the FreeBSD operating system running on our file server. By taking periodic snapshots of the live filesystem your files are stored on, we can easily recover old states of files.
Three levels of snapshots are available, hourly, daily, and weekly. Three hourly snapshots are kept onhand, taken at 10am, 5pm, and 9pm. Four daily snapshots, taken every morning at 1:15am, are available as well as three weekly snapshots which are taken every Sunday morning at 1:30am.
The best part about filesystem snapshots is the ability for each user to recover their lost data without the need for administrative assistance. Snapshots for home directories are accessible on fang by following the directory structure under /opt/recover/.To recover your lost data:
- ssh to fang.cs.sunyit.edu
- Type: cd /opt/recover
- If you type ls, you will see directories corresponding to the snapshot date. cd to the appropriate directory for how far back in time you would like to go.
- You are now in the /home filesystem as it was captured at the point in time you selected. Browse the directory structure to locate the file you lost.
- A step by step example of using snapshot data recovery is available.
If you have any questions, please stop by our workroom in Kunsela C122 or email the admins.
The CS department uses an Exabyte VXA-3 tape drive with a 10 tape changer for backups. 8 of the 10 tapes are devoted to home directory backups. These 8 tapes are in a 2 month rotation with 1 week's worth of backups saved to a tape.
Home directory tape backups are performed nightly. Full dumps (a copy of all files) are run every Sunday morning. Incremental dumps (copy only those files that have changed since the last backup) are done every other night of the week.
Should you need files restored from backup tape, email .
RAID Level 5:
The 3 primary CS file storage areas are on RAID-5 arrays to help prevent data loss due to disk failure.
With RAID-5, a filesystem is stored across multiple disks along with parity information. If any one of these disks fails, the others will be able to function based on what data and parity information is still available. A more detailed description is available here.