File recovery from a snapshot on Storage@Yale

Snapshots are read-only copies of the entire file system. The contents of each snapshot reflect the state of the file system at the time the snapshot was created. It is easy to navigate through each snapshot as if it were still active. Your directories and files will appear as they were at the time that the snapshot was created. A daily snapshot is taken every night, at approximately midnight, and a weekly is taken every Sunday, also at approximately midnight. These copies of your data do not count against your quota. A minimum of 7 daily snapshots and 7 weekly snapshots are retained. These are stored in a hidden .snapshot directory. The directory will not be visible, even using an "ls –a" command, but it is there.

What follows is a simple example of the procedure to recover a file. You will need to modify it as necessary for more complex directory structures, and for recovering multiple files at one time.

cd to top level Storage@Yale directory

[yournetid@login-0-0 ~]$ cd /SAY/standard/fas/yourgroup/yournetid

cd to hidden .snapshot directory

[yournetid@login-0-0 yournetid]$ cd .snapshot

ls to see available snapshots (7 days + 7 weeks)

[yournetid@login-0-0 .snapshot]$ ls
daily.2016-01-14_0010
daily.2016-01-15_0010
daily.2016-01-16_0010
daily.2016-01-17_0010
daily.2016-01-18_0010
daily.2016-01-19_0010
daily.2016-01-20_0010
daily.2016-01-21_0010
weekly.2015-12-06_0015
weekly.2015-12-13_0015
weekly.2015-12-20_0015
weekly.2015-12-27_0015
weekly.2016-01-03_0015
weekly.2016-01-10_0015
weekly.2016-01-17_0015

cd to desired date’s directory and ls to see available files

[yournetid@login-0-0 .snapshot]$ cd daily.2016-01-21_0010
[yournetid@login-0-0 daily.2016-01-21_0010]$ ls
saytest.txt testfile.txt

Copy desired file to desired new location with the same name

[yournetid@login-0-0 yournetid]$ cp /SAY/standard/fas/yourgroup/yournetid/.snapshot/daily.2016-01-21_0010/saytest.txt 
/SAY/standard/fas/yourgroup/yournetid/saytest.txt

Or to a new directory

[yournetid@login-0-0 yournetid]$ mkdir restdir
[yournetid@login-0-0 yournetid]$ cp –t /SAY/standard/fas/yourgroup/yournetid/restdir 
/SAY/standard/fas/yourgroup/yournetid/.snapshot/daily.2016-01-21_0010/saytest.txt