Overview

Within the LRZ web hosting service, your website data is regularly backed up. Data backups serve to reduce the risk of data loss that might occur in the case of a technical malfunction on our side or if you accidentally deleted important data yourself.

On the filesystem level, you have access to so-called snapshots. Snapshots contain previous versions of your website data. You can use these snapshots to restore files yourself (i.e. without the help of an LRZ admin). Your data is also backed up on magnetic tapes (TSM backup) from where it can be restored in the event of a greater technical malfunction. If you are also using a database along with your LRZ website, this database is also backed up on magnetic tapes.

You can find a summary of all backup variants in the table below.


Filesystem (via snapshots)Filesystem (via TSM)Database (via TSM)
Backup frequency
  • every two hours from 8 a.m. to 8 p.m. (7 snapshots total)
  • nightly (7 snapshots total)
  • weekly/on Sundays (3 snapshots total)
once per dayonce per day
Retention periodup to three weekssix months / ten daysten days
Who can restore the backup?You (and LRZ web hosting admins)LRZ web hosting adminsLRZ web hosting admins

File restoration via filesystem snapshots

To restore files from your filesystem snapshots, log in to your website via SSH using your website's functional account. Then change into the directory /nfs/web_<org>/.snapshot/ (remember to replace <org> with either tum, lmu, or mwn before executing the command).

Inside the snapshot/ directory you will find several sub-directories whose names start with either daily, hourly, or weekly. The directory names point to the time when the respective snapshot was created. For example, a directory called hourly.2023-01-25_0810/ was created 25 January 2023 at 8:10 in the morning. Inside a snapshot directory you will find your home directory under the usual path : www/<last_letter_of_functional_account>/<functional_account>/webserver/htdocs/.

Usage example: It is 9 o'clock in the morning on the 25 January. You are a TUM employee using the functional account 123abcd and you just deleted your website's very important index.html file. You can restore the file from /nfs/web_tum/.snapshot/daily.2023-01-25_0010/www/d/123abcd/webserver/htdocs/index.html

If you experience problems using the snapshots, please contact us via the LRZ servicedesk.

Filesystem backup via TSM

The number of older copies of a certain file and the copies' retention period depend on how often the file in question is changed (observing a maximum of 10 copies of a file and a maximum retention period of 180 days).

  • if a file is modified at least daily, there will be 10 copies.
  • If a file is changed only once a month, there will be six or seven copies of the file in the TSM backup. You will be able to restore all versions from within the last 180 days
  • If a file is never changed, there will always be only one copy in the TSM backup. If the file is deleted, the copy will be removed from the backup after 180 days.

If you cannot restore a certain version of a file or several files from your filesystem snapshots, please contact us via the LRZ servicedesk so that we can restore the file(s) from the TSM backup.


Database backup via TSM

The contents of your database are also backed up on magnetic tape (TSM). In case your database should become corrupted, it is possible to reset it and restore a recent backup. Please contact us via the LRZ servicedesk if you wish for this to be done.

If you would like to save your database contents locally, you may download a so-called database dump via our phpMyAdmin service.

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