# Backups

## Offsite Backup

SNS account home and data directories are backed up to an onsite datavault monthly and  synced to the cloud subsequently for disaster recovery purposes. Backups are retained for one year.

## Snapshots

Snapshots are local copies of the filesystem. While not a true backup from a disaster recovery standpoint, they are very useful since you can recover your own deleted files. Each snapshot image acts as a full backup at that instant in time.

Snapshots are conducted hourly, daily and weekly for SNS accounts.

On /home we retain one days worth of hourly snapshots , as well as four weeks worth of daily snapshots  and 52 weeks worth of weekly snapshots.

On /data we retain one days worth of hourly snapshots, as well as one weeks worth of daily snapshots  and 12 weeks worth of weekly snapshots.

Snapshots are located in a hidden directory named .snapshot within each physical directory. Use the cp command to recover a file from snapshots. To recover a file called somefile from the 3pm hourly snapshot use e.g.

cp /home/user/somedir/.snapshot/hourly.15/somefile /home/user/somedir/



## Mobile Backup

The IAS provides Crashplan, an online system that silently ensures your data is safe, by backing it up to servers at IAS. We urge you to use this simple and valuable service. We have licensed Crashplan for Faculty and for Members who have been provided with a laptop computer by SNS Computing.

Installation is simple.