# File Recovery on Tufts HPC Cluster

### Important Note

- These instructions only applies to the Tufts HPC cluster. 
- The snapshots are taken **daily**. The snapshot frequency may vary based on current policies and setups.
- Not all changes and modifications to all files are reflected in the snapshots. If a file is created, modified, and/or deleted within a couple of hours, it may or may not be captured in the snapshots depending on the timing.
- Snapshots retention period is **60 days**. Snapshots will be expired and deleted after 60 days.
- Do not modify or delete any snapshots. There is no snapshot of snapshots.
- The following steps need to be executed in Command Line Interface (shell, terminal, .etc). Users can access also access and recover files from OnDemand interface using the mentioned directory path.
- Snapshots can be accessed directly from any directories (usually the location of the missing files) on the HPC cluster!

## Example Scenario

In the following example, the target directory path from which directory the files/directories were missing is `/cluster/home/tutln01/work`. 

In your case, it can be any paths such as `/cluster/home/$USER/folder1/folder2` or `/cluster/tufts/yourlab/$USER/folder3`

### Find Snapshots

- Navigate to the target directory path: go to any directory (project or home, in this example, it's `/cluster/home/tutln01/work` ) where you need files to be recovered 
- Access to the `.snapshot` of that directory.

```
[tutln01@login-prod-01 ~]$ cd /cluster/home/tutln01/work
[tutln01@login-prod-01 work]$ pwd
/cluster/home/tutln01/work
[tutln01@login-prod-01 work]$ cd .snapshot
[tutln01@login-prod-01 .snapshot]$ date
Mon Apr 24 10:15:59 EDT 2023
[tutln01@login-prod-01 .snapshot]$ ll
total 0
drwxrwx--- 2 tutln01 facstaff 4096 Feb 24 12:36 homedir_2023-03-21_14_38_07_UTC
drwxrwx--- 2 tutln01 facstaff 4096 Feb 24 12:36 homedir_2023-03-22_07_00_00_UTC
drwxrwx--- 2 tutln01 facstaff 4096 Feb 24 12:36 homedir_2023-03-23_07_00_00_UTC
...
drwxrwx--- 2 tutln01 facstaff 4096 Feb 24 12:36 homedir_2023-04-19_07_00_00_UTC
drwxrwx--- 2 tutln01 facstaff 4096 Feb 24 12:36 homedir_2023-04-20_07_00_00_UTC
drwxrwx--- 2 tutln01 facstaff 4096 Feb 24 12:36 homedir_2023-04-21_07_00_00_UTC
drwxrwx--- 2 tutln01 facstaff 4096 Feb 24 12:36 homedir_2023-04-22_07_00_00_UTC
drwxrwx--- 2 tutln01 facstaff 4096 Feb 24 12:36 homedir_2023-04-23_07_00_00_UTC
drwxrwx--- 2 tutln01 facstaff 4096 Feb 24 12:36 homedir_2023-04-24_07_00_00_UTC
```

### Locate Missing Files/Directories

Choose the desired snapshot date. 

For example, assume I accidentally deleted a file from this directory on 2023-04-20, I would check both `homedir_2023-04-20_07_00_00_UTC` from 2023-04-20 as well as `homedir_2023-04-19_07_00_00_UTC` from 2023-04-19 for the desired version of the file. Repeat the following steps for both dates if needed.

Pick a snapshot date, and list the contents (our target directory is `/cluster/home/tutln01/work` in this case)

```
[tutln01@login-prod-01 .snapshot]$ cd homedir_2023-04-20_07_00_00_UTC
[tutln01@login-prod-01 homedir_2023-04-20_07_00_00_UTC]$ pwd
/cluster/home/tutln01/work/.snapshot/homedir_2023-04-20_07_00_00_UTC
[tutln01@login-prod-01 homedir_2023-04-20_07_00_00_UTC]$ ll
```

### Recovery Files/Directories

Find and verify the file/directory you are looking for, then **COPY** it back to your target directory under a different name (to avoid overwriting exisiting files).

- `-i` (Interactive): Prompts for confirmation before overwriting files.
- `-r` (Recursive): Copies directories and their contents recursively.

```
[tutln01@login-prod-01 homedir_2023-04-20_07_00_00_UTC]$ pwd
/cluster/home/tutln01/work/.snapshot/homedir_2023-04-20_07_00_00_UTC
[tutln01@login-prod-01 homedir_2023-04-20_07_00_00_UTC]$ cp -i myfile ~/work/myfile_recovered
```

If you are recovering directories, copy the directory recursively.

```
[tutln01@login-prod-01 homedir_2023-04-20_07_00_00_UTC]$ cp -i -r mydir ~/work/mydir_recovered
```

Now you can go back to your target directroy and check if the file/directory has been copied over

```
[tutln01@login-prod-01 homedir_2023-04-20_07_00_00_UTC]$ cd /cluster/home/tutln01/work
[tutln01@login-prod-01 work]$ ls -lrt
```

If you have multiple files/directoires need to be recovered, repeat the above steps.